A recent thread on cool iPod apps lead me to discover Dave Beckinghams video on the iReal Book $9.99 software for the iPod, shown here:
Unfortunately, I do not have an Ipod, or Iphone, or even an Android phone. This started me looking for something that would serve the same purpose and not cost a lot. I found and downloaded this open source (free) software called Impro-visor (click on the link below to go to its homepage)
It is really great, especially if you don't have a lot of buddies who play bass and drums and who you see everyday.
You can use it put in whole songs, and the instruments are sampled so they sound pretty real (as opposed to most midi programs on your PC). You can just put chords in and tell it what sort of beat you want and it will lay down a bass, chord and percussion track automatically. You can turn off any of them, and change the instruments that generate them. I have only had it a day, but I am trying to learn to lay down good bass and percussion tracks to use when I want to practice. So far, I am very impressed, and will probably do a demo video on YT when I learn how to use it a bit better. Sometimes I just let it do its own thing on the bass, and other times I have been giving it the actual notes I want the bass to play. That is kind of educational in itself.
As with most powerful programs, there is a bit of a learning curve, but I think it will be worth it. You can also download hundreds of backing tracks already set up for songs. Check it out, if you don't have an iPod, and don't want to buy something like band in a box. You can definitely learn to solo or play with others in a simulated band setting with this thing.