I think the first choice you want to make is if you want to use all IR or an IR/RF combo. If you want to use your existing remotes you would just get an IR receiver and a control block with flashers like this -
Niles Link
If you want to upgrade your remote as well then you could go to a RF/IR system. In this type your remote would output RF to a base station that would convert it to IR and feed to the flashers similar to the link above. The advantage here is that you would not have to point the remote at the IR receiver.
Edit: The link that Adam posted is a very cost effective solution. The Niles I linked is much more expensive and has no real advantage that I can find.