Since Tupac's death, there has been a struggle over his estate.  Now, people, many of who were too coward to file a suit while he was alive, are seizing the opportunity to grab part of the estate.  Here's a breakdown of some of the law suits that have taken place.  Everything here is correct to the best of my knowledge, if you have any further information or feel that something here is incorrect, please let me know.  If you have a Tupac site and want to use this, please let me know and give me credit where it is due.
  

BadAzz vs. Deathrow

Badazz is suing Deathrow for $500,000 over the song he did with Pac on the Makaveli 7 Day Theory CD, "Krazy".  Apparently he wasn't paid any royalties for the song.

Afeni Shakur vs. Deathrow

Successful lawsuits were won by the estate to gain merchandising rights to Shakur's image, which means it would receive royalties from T-shirts, posters, hats etc., and they also won a suit against Deathrow to gain the rights to unreleased material. A $7.1 million suit by Death Row Records, demanding reimbursement for cash advances that Shakur allegedly used for cars, houses, jewelry and other expenses. The estate filed a 41- page counter suit, accusing Death Row of looting $50 million from Shakur to maintain the extravagant lifestyles of label head Marion "Suge" Knight and other executives.

C. Delores Tucker vs. Estate of Tupac Shakur

A $10 million lawsuit by C. Delores Tucker, a virulent opponent of gangsta rap. Tucker, who once labeled Shakur's music "pornographic smut," claimed lyrics on Tupac's 9 million-selling album "All Eyez on Me" were so demeaning that it affected her sex life.  Two songs derisively mentioned Tucker by name. On one, "How Do U Want It," Shakur rapped: "Delores Tucker, you'se a motherf*cker/Instead of trying to help a ni**a, you destroy a brother", the other song is "Wonda why they call u B*tch." Read the Official Court Document

William Garland vs. Estate of Tupac Shakur

A lawsuit was also filed by Tupac's father, William Garland, seeking 50 percent of Tupac's Estate.  Garland had little contact in Tupac's Life and until Tupac got shot in '94 Tupac believed his father was dead.  He was only trying to make money off of his blood-only son.  The case was previously thrown out of court, but ended in a settlement of $540,000 plus legal fees totaling just over $350,000.

Jacquelyn McNealey vs. Estate of Tupac Shakur

Jacquelyn McNealey was shot and paralyzed by a stay bullet at a 1993 Tupac concert in Pine Bluff, Ark. Fischbein.  She claims that Tupac got the crowed all fired up, resulting in her being shot.  A November 1996 court award of $16.6 million was overturned when it was ruled that Tupac's estate wasn't allowed to present a defense at the trial.  She later settled for $2 million.

Whitwells vs. Estate of Tupac Shakur

Two off duty policemen claimed they were crossing the road and were almost hit by a car back in 1993.  They got into a dispute with the driver, and 2 other cars pulled up, they claim they ran but were shot in the buttocks.  Witnesses later identified the shooter as Shakur, who was in town for a concert and staying at the same hotel as the Whitwells.  "Criminal charges were dropped when it emerged that the policemen had been drinking and had initiated the incident, and when the prosecution's own witness testified that the gun one of the officers threatened Tupac with had been seized in a drug bust and then stolen from an evidence locker."  Civil suit with one officer was settled out of court, the officer in this case was awarded the amount of $210,000.

Johnny Lee Jackson (Johnny J) vs Deathrow

Johnny J. says he co-wrote and helped produce 11 songs on All Eyez on Me and was never paid the $100,000 advance or the per song royalties of 3% he was supposed to receive.  I'm assuming there are still hard feelings between him and Deathrow as the word Deathrow was edited out of songs he produced for the album "Until The End of Time."

Orlando Anderson vs. Estate of Tupac Shakur

Orlando Anderson, a crip considered a suspect in the shooting of Tupac, was beaten by Tupac and Suge in the lobby Sept, 7, 1996 of the MGM theater the night of the Tyson fight and Tupac shooting.  Although Anderson was later killed in a driveby thought to be linked to the shooting of Tupac, a suit against Tupac's estate will continue.  Suge was ruled to have been responsible in the beating and sentenced to a 9 year prison sentence for violation of parole.

R&S Antiques Inc vs. Estate of Tupac Shakur

A Beverly Hills Jeweler is suing the estate claiming Tupac had an unpaid tab of $38,000 for a white gold and diamond bracelet and a $45,000 medallion designed by Gianni Versace.  R&S Antiques Inc is seeking in access of $93,000 for the jewelry and interest on it.

Afeni Shakur vs. Orlando Anderson

Sept 16th, Afeni Shakur filed a wrongful death suit against Orlando Anderson.  Afeni Shakur's lawyer, Richard Fishbein, says the suit was filed because, "The Las Vegas police have as much interest in solving this crime as the man on the moon... I believe I cannot do any worse than they have."

Jaques Agnant vs Estate of Tupac Shakur

In the song "Against All Odds" which appeared on the post humorous album, Makaveli, Tupac labelled Jaques Agnant a snitch.  A former friend of Tupac Jaques Agnant had ties to the Black Mafia.  He was friends with the woman who accused Tupac of rape in 1994.  Although Jaques Agnant aka Hatian Jack, was involved in the incident they had separate trials and Agnant got off while Tupac was sentenced to 4 years in prison.  Tupac referenced this in "Against All Odds" stating "Same crime different trials."  After the death of Tupac Agnant filed a suite against Tupac's estate for over $200 million claiming that because of Tupac's song he couldn't find work and was afraid for his life after being labeled an informant. Read the Official Court Document