One of the best (IMHO) and FREE CAT software packages out there is Ham Radio Deluxe (HRD) by Simon Brown, HB9DRV. The list of radios that you can use it to control is truly massive, and the features it offers are incredible. You can get the software from Simon's website - http://hrd.ham-radio.ch
I tried many trial/shareware CAT control programs, and even resorted to writing my own Java-based CAT control program to control my FT857-D. Despite all of this, I still run my rig with HRD. It's an incredible program!
I even recommended this program to my Yaesu dealer - he hadn't heard of it! I understand that they are now going to give out a copy of HRD with each Yaesu they sell. How's that for an endorsement!?