If you've been riding with toe clips and not tipping over, clipless is easy. Any decent system will work better and easier than toe clips.

My suggestion for cheap pedals:
http://www.nashbar.com/bikes/Product...0052_512515_-1___

I've had the single-sided Shimanos and others. Do. Not. Like.

The eggbeater clips in and out fast, and with the cleats on a certain way they have a lot of float, something like 12-15 degrees.