Drum Beats for Practice

It would be fun to have some basic drum beats to practice the uke to.
Everything I've found online requires you to create your own loops.
Does anyone know of something (free) that just plays basic pre-made drum loops: "rock" "jazz" and etc, that you can change the tempo of? Windows or iPhone

GarageBand for iPhone has some basic loops. 5 bucks.

Garageband will do what you want to do. Another choice that I prefer is the "iReal b" app. http://www.irealb.com. You're able to have basic bass and keys accompaniment also. On their forums you also have access to thousands of charts for songs that you can play along with at any tempo. It's a few dollars more ($7.99) but well worth it in my opinion.

I use Drums Loops on Android. Free.