Leader Training:This is training with your allience leader.You must do this everyday for a week for it to be effective.It's kinda slow but easy way to gain levels and experience.
Master Roshi:This is training on Earth with Master Roshi.After 5000 Zenny and 5 days,you'll be 5 levels higher and able to perform Destructo Disk and Destructo Disk x2.This is recommended for begginers but the 5 levels up are a nice touch too.
King Guru:This is training on Planet Namek with King Guru.For 7500 Zenny and 6 days,you'll have 5 levels up and be able to perform Makankosappo.This is also for begginers more or less but don't under estimate the move.It can be very deadly if performed correctly
King Kai:This is training with the legendary King Kai.It cost 10000 and you can't do anything else for a week.But at the end of that week,You'll be able to perform Spirit Bomb,one of the greatest attacks in the game.
Bardock:This is training on Planet Neo-Vegeta with Goku's father,Bardock.For 12500 and 8 days,you'll be able to perform the Eye Laser and Fire Breath techniques and you'll be 7 levels higher.Recommended for a more intermediate player.
King Vegeta:This is training on Planet Vegeta with King Vegeta.For 15000 you'll be 8 levels higher and be able to perform Galic Gun,Big Bang and Final Flash.Its a good idea to train with King Vegeta becuaser you'll get alot of levels and some hard hitting techniques.For Intermediates also
There will be more types of training to come.Until then,Enjoy!