[LazerBlue]

Sounds like you should look at FLIRC. It's a USB IR receiver that you can program from within Windows, OSX or Linux (and it can be programmed on other machines, not the machine you want to use it on). You can use it with any mainstream consumer IR remote control and it will appear as a standard USB keyboard to the machine it is connected to. Not dirt cheap - and it may well be cheaper to buy an RC6 remote control (that will work with the IR receiver in the current NUCs) but if there is a specific remote you want to use, FLIRC may well be the least painful solution.

Isn't there a FLIRC like software that will work with the built-in IR receiver? I really don't want to add any hardwar on the outside, if I can help it. Of course, if there isn't, I'll look into an RC6 remote, or keep using the PS3 bluetooth that I am using now.

There's even a chance that some remotes you have now will work. My old Verizon cable box remote has a code for Windows Media Center that worked for me on the last and a lot of universal remotes that are out now seem to have codes for Microsoft and MCE available.