Here you'll find some links to the open source software I've developed (either entirely or partially... well, for the most recent one merely I might just have had the time to code a few lines...).
Tstat, a purely passive traffic analysis and monitoring tool
DiaNa, a tool for the analysis of large datasets
Wetmo, a web traffic generator for ns2
Mottix, a TinyOS sensor network data sniffer and analyzer
If ever I have time (so with very low probability), I'll put a series of perl scripts that I find useful