If memory serves me right, I've talked before about the lack of support that SQL Server 2005 will provide for Access 2000 and my advice has been just say no! The primary reason for this is that the internals of SQL Server 2005 will be considerable different: just consider the XML type, for example. Access 2000 was geared toward SQL Server 7. There's been reports of some features of Access 2000 just not working as well as they should with SQL Server 2000.
But I feel that Mary Chipman put it best recently in one of the SQL Server 2005 newsgroups.
...the Access upsizing wizard will only work with SQL Server 2000 editions. There are no plans at this time to rewrite it to work with SQLS 2005. You will also not have the capability to create or modify SQLS 2005 database objects in an Access project (ADP), only to use it as a front-end connected to a "finished" SQLS 2005 database running in SQLS 2000 compatibility mode.