Where i can buy the keyboard for garage? and what other else has to buy to start my garageband?

Question

Where i can buy the keyboard for garage? and what other else has to buy to start my garageband? I am a beginner for garageband. Thanks.

Answer 1

I second the M-Audio recommendation.  I have the Oxygen 8 and 61es keyboards from them, and they both work flawlessly with Garageband.
what other else has to buy to start my garageband?
This depends on what you want to do with Garageband.  Do you want to record with a keyboard only and just use Garageband's built-in software instruments? Do you want to record vocals? Do you want to record a guitar or bass or other instrument?  Do you want to record drums?
Technically, you don't even need a keyboard to use Garageband, you could just use the software keyboard (Window -> Keyboard) or musical typing (Window-> Musical Typing).  However, an external keyboard will give you a lot more flexibility.  I don't recommend trying to record drums into Garageband unless you already know how to mic drums.  Instead use the built-in drum kit software instruments with your keyboard.
Your iMac has a built-in mic, so you should be ok recording vocals with that.
If you want to record an acoustic guitar or another acoustic instrument, you can also use the built-in mic though you may find that you don't like the way it sounds very much since built-in mics tend to pick up lots of noise from the computer itself. 
If you want to record an electric guitar or bass, you can just plug in the line out on your instrument to the line in port on your iMac, but you won't get really good results.  You'd be better off geting a piece of hardware called an audio interface  Sweetwater sells these too:  http://www.sweetwater.com/shop/computer-audio/audio_interfaces/ (USB and Firewire interfaces are easiest to start with.)  M-Audio also has some good cheap interfaces.  I've used the FastTrack Pro for a few years now, and I started out with the FastTrack USB.
Ok, that's probably more than you wanted to know...happy Garageband-ing!