As per BOL the max number of table in a SELECT statement is 256.

Here is something from Inside SQL Server 2000

Multiple-Table Joins

According to some folklore, SQL Server "does not optimize" joins of more than four tables. There was some truth to this in earlier versions of SQL Server, but in SQL Server 2000 optimization doesn't happen in the same way at all. There are so many different possible permutations of join strategies and index usage that the query optimizer goes through multiple optimization passes, each considering a larger set of the possible plans. On each pass, it keeps track of the best plan so far and uses a cost estimate to reduce the search in succeeding passes. If your query contains many tables, the query optimizer is likely to interrupt the last pass before completion because the last pass is quite exhaustive. The cheapest plan found will then be used.

HTH