Joining two networks

I have two distinct networks sharing a fast fibre backbone through Cisco Catalysts and 3Com hubs. They both use private addressing, one is 10.0.0.0 and the other 192.168.1.0. They are currently separated by Vlans on the switches. I want to run a database that users on both legs can use, but maintain the separation for security and resilience. If the database is on a Win2k box running SQL Server 2000, what is the best way to do this? The 10.0.0.0 network runs on Small Business Server 4.5 (singleserver with no trusts allowed by SBS) and the 192 side on NT4 SP6a (five machines). What is the best way to glue in the new database server? Can you offer wisdom to a keen but under-trained netman please?