Opera mobile 11 emulator for desktop:
http://www.opera.com/developer/tools/mobile/
Opera mini 6 emulator (Java?):
http://www.opera.com/mobile/demo/
For webkits - its realy messy, as they are slightly different from each other..
For old browsers .. just buy/lend/borrow phones you think are important, or ignore them (serve simple html content), if you CAN'T provide any adequate testing.
More on topic:
http://www.mediawiki.org/wiki/Mobile_browser_testing