Three player all-in with a tie
The answer will depend on who has the most chips.  Let's assume that there are 3 players, A, B and C.

A has 100 chips, B has 50 chips, and C has 10 chips.  All three go all-in.  There will be two pots.

The first pot, called the "Main Pot", will have 30 chips in it, 10 chips each from A, B, and C (the value of C's all-in). A, B, and C are eligible to win this pot.

The second pot, call the "Side Pot", will have 80 chips in it, 40 from B and 40 from A, the value of B's all-in.  Only A and B are eligible to win this pot.  

A still has 50 chips on the table that is not in a pot.

If C loses:
- A and B split all of the chips in both pots evenly.
- C is eliminated. A has 105 chips. B has 55 chips.  

If B loses:
- A wins the 80 chip pot, A and C split the 30 chip pot.
- B is eliminated. A has 145 chips. C has 15 chips.  

If A loses:
- B wins the 80 chip pot, B and C split the 30 chip pot.
- A has 50 chips.  B has 95 chips.  C has 15 chips.