Hang to the rescue
Liero AI: Reverse engineed Liero, thats open source. Runs on XP, has mountain of new features.
http://helios.et.put.poznan.pl/~ssko...iero/news.html
Soldat: A Liero clone. Lots of people love it, I never really got into it. Slighltly more realistic than Liero, such as it has people instead of worms and has real life weapons.
http://www.soldat.prv.pl/
Tunnels of Underworld: Simliar to Liero, but you play as aircraft. You can build gun turrets, deploy troops and trucks, and has lots of other nifty features like two player split screen.
http://www.tou.has.it/