You might also want to look at the PowerLinc
Controller from Smarthome
http://www.smarthome.com/1132CU.HTML If purchased with the "Plus" software, it
will then also do conditionals. Since I was
tired of waiting for X10 to come out with a
CM11 replacement that actually worked (AHP
still has a ways to go), I switched over to
the PowerLinc Controller several months back
and haven't had any problems with it. Don't
know if Smarthome has an SDK available for
it, though.