Microsoft® SQL Server™ 2000 retains the 900-byte limit for the maximum size of an index key but changes the algorithm used by CREATE INDEX to check if the specified index key exceeds the maximum allowable key size of 900 bytes. The new CREATE INDEX algorithm is similar to the row size algorithm used for CREATE TABLE.
More Information:
SQL Server 2000: Maximum Size of Index Keys
SQL Server 2000: Maximum Capacity Specifications