Iphone apps that give you more space for streaming music?

I have an 8GB iphone 4s but I have so many songs and if i put all of them on my phone then i won't have any space for apps and i like apps XD
are there any apps that could store my music and play it similarly to the iphones music app? I downloaded dropbox and it lets me stream music but its very slow and i can't shuffle or anything. So if anyone knows anything, help please.

You can stream music from you're itunes account onto you're 4s.

Get pandora it is the best you just put in a few things you like about music and the rest is cake it finds songs that you like and similar to the ones you like it could even broaden your taste in music and if you don't like a song you can just skip it.