NBA Live '99 cheats and cheat codes for Nintendo 64

Ball Flip
When at the line, hold R before shooting the ball to flip it.

Granny shot.
While shooting a foul shot, hold C-Left

Bonus teams
Go to the "Rosters" and choose the "Create Custom Team" selection.
Type one of the following locations and team names to unlock bonus
teams:

Location - Team name
Hitmen - Earplugs
Hitmen - Pixels
EA - Europals
Hitmen - Coders
Hitmen - Idlers
Hitmen - Rebounds