Here's good old http://companyweb on SBS 2003 running under Sharepoint v2
Now here's the same http://companyweb running on SBS 2008 after I had migrated all the content across:
There's no trick photography, sleigh of hand or digital retouching here I have successfully been able to migrate Sharepoint v2 data from SBS 2003 to Sharepoint v3 in SBS 2008.
Having been able to migrate successfully before from Sharepoint v2 to Sharepoint v3 I knew that it would be possible but wanted to make sure on SBS 2008. I will admit that there is trick or two unique to SBS 2008 I had to overcome before I could get it working but nothing major. Now that I know it can be done I will go back and work on improving the process further.
Subscribers to my Windows Sharepoint Operations Guide (WSSOPS) will soon be see a new chapter dedicated to the full migration process of companyweb on SBS 2003 to SBS 2008. If you aren't a subscriber then you are going to face some hurdles but nothing that isn't insurmountable given the information current out there on the Internet. I will save you a bit of time and say that you can't simply backup Sharepoint v2 and restore it to Sharepoint v3. The rest you'll just have to work out for yourself, sorry.
I need to have a closer look at migration options that Microsoft now has with SBS 2008 but I have a feeling that they don't have anything for Companyweb, which I think will concern quite a few people. I may be wrong but I'm sure there are plenty or people who will want to migrate SBS 2003 companyweb to SBS 2008 companyweb but maybe I'm wrong?