The next version of SQL Server, code-named "Sphinx," will likely support 64-bit code, allowing it to support data warehousing. Originally, 64-bit support was expected in the 1998 release, to coincide with other 64-bit offerings, but Microsoft wants to get the release ramped up as quickly as possible. A 64-bit SQL Server would run on the 32-bit NT Server by creating API "hooks" that implement a psuedo-64-bit interface.
The 64-bit implementation of SQL Server will allow Microsoft to create a terabyte-sized database. The current implementation is limited to 200 GB