A recent article talked about geeks providing support for friends and family. If you're one of these people, I recommend that you build yourself a small toolkit. Put it on a mini-CDR or a thumb drive and carry it around with you (128M thumb drives go for about $35 now).
In any case, one of the tools that should be in that toolkit is Ad-Aware. This tool is capable of removing most current spy-ware binaries. I've only seen one that it didn't recognize/remove and that'll probably be included in the next release.
Another recommendation, maintain a text file with pointers to the download site for your tools and pointers to any professional versions of the software that you use. You never know when you'll end up "doing a job" for a company.