There's an album that's only avaliable on iTunes Store and I really want it. Is there any way I can get it on Ubuntu 11.10?
Unless Apple release a web-based version, the only method is to use Itunes. I discuss methods of using itunes in another question: What is the best way to run iTunes?
Wine currently doesn't deliver that awesome an experience and given you only want to buy one album, VirtualBox might take too much time to bother with for just one album.
You might have the best luck just writing directly to the artist and explaining your woe. Let them know what you're happy to pay and see if they can sell you a CD directly. It might prompt them to add their music to more than one online store.