I experimented with two options;
- Cross-browser testing was done using the service at BrowserCam, which I was very impressed by. The free trial on that site allows for testing across a sizeable combination of browsers and operating systems (from FireFox 1.5 on Linux, through Safari 2.0 on OSX10.4, right up to IE7 on Vista with most other combinations you'd ever need in between), and the pricing looks very reasonable compared with the difficulty of actually hosting the numerous combinations.
- Mobile browser testing using the online Opera Mini simulator at http://www.operamini.com/demo/?url= Just add the URL you want tested in the query string, and you'll see your page presented in the Opera Mini. Note that there are some other mobile browser testing options.
Another option I have not yet tried is the BrowserShots site (currently in a 'Technology Preview' state).
The goodness of web standards shone through during the cross-browser testing. The site rendered well in all combinations of platform and browser apart from IE5.2 on the Mac (which seems to have problems with background images). And the site even worked well in Opera Mini once I had hidden an image and some promotional text using a stylesheet tailoerd for handheld media.
Which all goes to show that applying XHTML, semantic markup and all those other best practices really does work!