Hi,
our client wants to change from Sharepoint 2.0 to 3.0. Of course they need all documents to be migrated too. I have some experience with 3.0 -> 3.0 migration, but that's all.
Main requirements are:
Thanx in advance!
You can perform an upgrade install which will upgrade your existing 2.0 site to 3.0. It is outlined in this Microsoft document which should provide the info you need, and there is more information here as well. I have used this process in the past and it does keep the documents intact and is usually relatively pain free. Just make sure you make some site collection backups as well as DB and IIS backups before you start as the upgrade isn't easily reversed.
Using a tool like Quest's Migration Manager may be something to consider, especially if the 2.0 site needs to be live and updated during the migration process. It's not cheap, but it can handle changes that occur during and after migration while you are still waiting to make the new 3.0 site live.
I've had a lot of success doing this with Metalogix SharePoint Site Migration Manager. It migrates all the attributes you listed plus things like permissions and views. It can also run on the client with only a small server install and is very easy for an end user to manage (if that's of benefit to you).
Any process without using a third party tool tends to be pretty clunky and laborious. Save your sanity and use a third party tool.