The latest version of my favourite platoon-level SF skirmish rules has now arrived! Fast and Dirty is an excellent set of absolutely free web-based rules written by Ivan Sorenson. They have a lot of the flavour of another favourite of mine, Stargrunt (focus on squad level fire, effects of coming under fire and pinning et), but are aimed to play a lot quicker. Now before I go any further I'd better admit to a little bias, as Ivan was kind enough to let me input some ideas into this latest version (most of which than had to be turned into something more workable!), as well as some of the artwork.
One of its best features is that they are incredibly easy to customise. A series of 'traits' allow you to tailor forces to create just about any SF archetype you can imagine, from soulless killer robots to zombie hordes, through bugs and genetically engineered supersoldiers. With the addition now of things like psionics, more detailed vehicle rules, and a task system to allow more of a role-play element.
There's even a basic campaign system included!
I'd heartily recommend it to anyone after a simple, yet comprehensive, set of rules for anything from WWII to hard SF style games.
You can download the rules here: http://www.freewebs.com/weaselfierce/
There's also a Yahoo group here: http://groups.yahoo.com/group/fastanddirty