Icom makes a line of handheld programmable scanners. Th most popular one in their line among RCers is their IC-R2. It isn't the easiest one to use, though.
http://www.icomamerica.com/receivers.../icr2main.html
Aerografixs imports the "Model-Scan" - this is one of the better scanners you can get.
http://www.geocities.com/roger_forgues/Frequency.html
You can also check your flying area for non-RC related potential interference sources (pager towers, railroad switching equipment, misc industrial gear, etc. etc.) for
free! I've posted an explanation and HOWTO; here's the link.
http://www.rcuniverse.com/showthread...964&forumid=27]