Interface or iStudio Adaptor ?

Hi guys. My 2.4Ghz 2 GB Macbook will be arriving in the next couple of days. I am looking forward to getting onto Garageband and making some music to put on myspace.

To get instruments into garage band i have bought the Monster iStudioLink instrument adaptor.

However everyone one seems to be talking about bloody interfaces. What are they and are they really needed?

many thanks

The Studiolink link should be good enough to get you started. Interfaces is use to get the best possible sound quality. The input on the macbook is okay but not great. You can also use the interface as a pre-amp for you mic or guitar, depending on what kind of interface you get of course.

The cheapest(cost wise) interfaces I can think of is M-audio. They have a few that are under a hundred buckaroos.

Hope this helps.