Just thought you might be interested in this accessory which I recently bought on eBay. The reason I bought it was that I no longer have an iPhone or iPod so I thought it would be good to use my iPad as a music player when I'm at home.
I am very pleased with this so far. When you first use it, it asks you to install an app which is free. This gives you a special iPod screen and some other stuff for viewing photos and weather stuff, but really it doesn't add a lot. The sound quality is good and is a lot louder than the built in speakers. Also it comes with a little remote control so you don't have to keep touching the screen to change track or volume. This is great if you want to listen to music whilst cooking (which I do a lot).
It cost £60, and all in all I'm pretty pleased with it.