@BroHogan did you have to modify the code at all to get it to work?
I was able to hear the x10 rf "sounds" over the steady beep beep beep coming from the 315 receiver and tuned that to double or triple the reception distance. (~160* CCW)
I've then got it wired into the arduino like so: lookout: X10 RF & IR remote using Arduino
and have loaded the X10_test sketch to the arduino.
Problem is, I'm seeing the "X10" startup message over serial, but nothing when firing an x10 rf controller. Adding some logging to the X10rf lib I can see the receive() function is firing 10+ times/sec but not sure what I should try next. @ThomasM any troubleshooting tips/things to check?
Thanks!!
Edit: Nevermind 
I guess the signal was too weak. Adding an antenna it seems to work great!
Edit2: I found that some of my wireless remotes wouldn't work. The mini keychain one worked fine as its signal came out alot faster (I found this out via the audio technique) than the palm pad remote. I adjusted all of the max time values in X10rf.h to 25000, 2200, and 3300 respectively and now it works great! Sweet!!
Thanks for your great work Thomas!