If you've got any time to spare, check out the Cloth Editor at Polyvore.com - I really love to play with it, whenever I allow myself a break from school stuff or household chores. You have to register to have full access to the website's features - I didn't and still get to use it to search for cool stuff and compose outfits (I just make a screenshot instead of using Polyvore to archive my compositions)... So this is what the editor looks like:
I really don't know what else one can do with Polyvore, but if someone's got an account there, maybe you could tell us if it's worth subscribing. In the meantime, I'm going to use their site for browsing the endless world of clothes and accessories *sigh* I SO am a girl - I just can't help it.