1. Go to the manufacturer's web site, if they still exist, and see if they have a manual there
2. Search Google for "MODEL# pdf". Wade through pages of pond scum search engine spam and paid sites for a half hour. Apparently, enough people search for manuals to make this profitable.
3. Do some web research to find similar product model numbers (maybe 8029A manual would cover 8029B too?) and repeat 1-2 above.
4. Start searching through forums and other hard-to-index parts of the web.
5. Check torrent sites? (now I'm getting desperate!)
It's crazy how tough it can be to find a user manual. In many cases, I end up finding one scanned by another end-user and posted online to be helpful. It's also a shame that 1/2 the comments here are about copyright. I can't see how taking a site like this down would in any way benefit a manufacturer whose manual is available. Unless the manufacturer is trying to make money selling their user manual, in which case to hell with that shitty company.