Wow, this thread had fallen onto page 2 already.. Threads don't stay high in the off-topic forum these days!
Anyway, just wanted to provide a little bit of an update. I got two sets of the X10 Powermid's for remote redirection, and they work great. Then this weekend I got the IRman and eagerly tried it out with the Girder software you recommended and it's fantastic. Very full-featured, if a little bit quirky and tough to understand in the first five minutes... But within a half hour (not counting the time I thought I had plugged it in when I had accidentally plugged in my PocketPC sync cradle instead) I was programming different groups of codes for different applications depending on if they're in the foreground, etc. Adding in a button to switch to specific application and I was pretty much set. Now I can control WinAMP in my bedroom from my living room with relative ease.
The mouse movement stuff isn't too difficult either. I also did the small/big mouse movements thing and in a pinch (to do something I haven't scripted yet) it's not too bad. This Girder software has so many plugins and a lot of powerful capabilities I haven't even touched yet, but I'll get there.
Thanks for all the recommendations, everybody.