how about buying the domain name?

Yep, but most of them involve blunt, rusty objects so I'll hold my piece.

Only ethical thing I could suggest is going down the trademark type route in court etc. Not sure how quick/successful this could be (I'm guessting , 'not very') especially as I'm guessing the domains are registered by parties 'over-seas'.

Unfortunately, I think this is likely to be something that just 'happens', at least until user training/awareness is at a level that people spot these sites, realise they are in the wrong place and re-type the URL. At which point the commercial gain from running the sites should take a hit.

None of this is likely to help your particular situation any time soon though, sorry. From similiar experiences I find these are 'grin and bear it' moments. Hopefully you can prove me wrong...

i think most people do that for a quick buck.  how quick and how big that buck is will depend on how big and important the real domain name is.

i'm pretty sure just buying the domain will be cheaper than any litigation but still feeds the POS that do that sort of thing.

Chris:
Yeah, I agree. I'm hoping it won't go that far. We had something similar happen with some people stealing content from our website, then building their own site to impersonate our company. The registrar/host was GoDaddy, and once we informed them they had no problem taking control of the domain and canceling the hosting. Hopefully we'll get something nice and quick like that done this time.

Brian:
Thanks for the tip. I had not thought of that before. That doesn't seem to be happening for my specific case this time (as I am able to get whois info -  private registrations), but I will definitely check into that the next time I see this happen.