Using kill, you can pass signal 0 which is essentially a pid ping. This is apparently the most portable thing I've come across for this. And, o yeah, don't forget that I actually meant sigqueue instead of kill. :-D (POSIX dude, ovrnout)

AgentM Systems nor Nasca Enterprises nor Bone::Easy nor Macperl is responsible for the comments made by AgentM. Remember, you can build any logical system with NOR.