Ok so I thought that I would send out a little update to this... I have now been working on the migration for about a month (on and off) and am just finishing off.
The one thing that is noticable with the change is that the masterpages in 2010 foundations are much more tied down than they were in wss3, for example, in wss3 you could emulate MOSS navigation with a quick change to the "topnavprovider" essentially allowing dynamic dropdown menus with ease. In 2010 the same is not true. It appears that ms are spending more time on differentiating the foundations product from the full server product and making it harder to emulate the look, feel and features of the full Server product in the free foundations product. To do this it appears that they have tied the navigation providers deeper into publishing infrastructure (a feature not available in 2010 foundations), I thought that this was going to be a big problem, that was until I realised that we could probably use ajax to build a new nav menu or just overide the current one with a new nav provider (work in progress here) however for the time being I have reverted back to the WSS3 masterpage and we are going to do our first release on this.
Moving on everything else has been pretty easy, granted I stumbled across changes in the object model that meant my custom code had to be modified to work on the new environment, these changes included moving base events to their own method, changes in the syntax for event firing and the disabling of as well as configuring myself a new deployment method (for some reason my old custom app just doesn't seem to be doing a decent job anymore).
Ok on to FBA, if you are currently running alternate access mapping on WSS3 and are thinking of upgrading then be aware that FBA is a whole new animal in this version. There were no major issues with the configuration but importing the user accounts and passwords from WSS3 into 2010 is not something that I have managed and to be honest it doesn't bother me a whole lot as the passwords were generated and emailed to myself as well as the users in question. This one boils down to re-keying.
So out of the box the upgrade does pretty much work excluding the following items:
- GAC deployed code - for obvious reasons when moving server you will need to re-deploy the code to the GAC, this is after making the subtle modifications required by the new environment.
- Workflows - Need to be re-registered, there was not a single change needed here just linking to a list in designer.
- FBA and other Alternate access mapping.
Finally, and I forgot to mention this... when we first detached the database to take a copy, after the detatch the following things broke in the WSS3 environment (our live environment).
- Search server (application error and failed searches for users)
- Central admin (Application error connecting to the database)
- Alerts (Our old WSS3 server just refuses to send out alerts... This is still not fixed but we are surviving till we decide to go live.
Some resources (books) which I would recommend for anybody playing with 2010 and WSS3 for that matter:
Office SharePoint Server 2007 - Administrators Companion (simply a must have for WSS3 and MOSS)
SharePoint 2010 Administrators Companion (as above)
Finally, and I am still waiting on delivery of this because it was only released today but should help with my butchering and branding of the UI:
Professional SharePoint 2010 Branding and User Interface Design