Define software? If you're talking about frontends, the big two are Ride Runner, and Centrafuse. OpenMobile is rapidly getting larger, and will likely eventually be considered one of the big ones. Look in the Frontend section of this forum. There is a huge list of available frontends, most of them small and still under some development, but those are the main ones.
There is also a variety of other misc. software that is useful. Here are some links for you to check out: