Garageband, all-around, is a great site. The offer a forum and can offer unlimited MP3 hosting of your band's songs. The main feature of Garageband is the peer-review system. It's designed to encourage the reviewers to say something a little more insightful than 'i liked it a lot', so it can be a great place to get some constructive criticism at the very least. If you have an account with CDBaby (also highly recommended), you can link to your CDBaby account so anyone interested in your music can easily purchase it. The rankings can potentially give you some exposure and I've even gotten a couple of sales from Garageband personally, though keep in mind that most of the people reviewing will probably also be musicians who are looking to sell their own music and not necessarily people looking to shill out money on someone else's music. Still, at the very least, it can be a great place to rack up some free reviews to use on your myspace or homepage...