Virtualdub and maybe Virtualdubmod, though they may or may not be able to read MPEG2 files.
Vidomi can read MPEG2 files, but it only outputs in AVI format. I'm pretty sure that there's a mod of bbMPEG out there that works as a Windows codec, but I only found it once long ago, and haven't seen it since - this allows MPEG2 output.
Other than that, for pay-for software, I'd recommend Ulead's Videostudio 7. It is $100, but it is functional - it allows for commercial elimination, and general video editing. It has an option to just output the raw MPEG2 data - it just clips out the parts you don't want, without re-rendering anything; they call it Smartrender. Or you can downsample the files, and then put them on a CD or DVD. It outputs in MPEG2, MPEG1, AVI...and I think Quicktime and RealMedia as well. I use it to put a few TV shows I like onto DVD - it also lets you create menus for the discs. There's a demo at Ulead's website, which gives you a functional version of it to try for 30 days.