how to check if linked server exists

how to check if linked server exists in SQL Server 2000:
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Select 1 Where Exists (Select [SRVID] From master..sysservers Where [srvName]='PSQLWEB1')


how to check if linked server exists in SQL Server 2005:
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Select 1 Where Exists (Select [SERVER_ID] From sys.servers Where [Name]='PSQLWEB1')