Which version are you using? SQL 2000 or SQL 2005?

If 2005, in the publication wizard, when it reaches the snapshot agent section, make sure you have both the Create Snapshot and Schedule Snapshot unchecked (Ok..This is how I did it.There are others who have better knowledge than me who can say if I wrong or if there is better way to do it).

If you are running as a script, it will look like this

exec sp_addpublication @publication = N'Test', @description = N'Transactional publication of database ''Test'' from Publisher ''TestSrv''.', @sync_method = N'concurrent', @retention = 0, @allow_push = N'true', @allow_pull = N'true', @allow_anonymous = N'false', @allow_subscription_copy = N'false', @add_to_active_directory = N'false', @repl_freq = N'continuous', @status = N'active', @independent_agent = N'true', @immediate_sync = N'false', @allow_sync_tran = N'false', @autogen_sync_procs = N'false', @allow_queued_tran = N'false', @allow_dts = N'false', @replicate_ddl = 1, @allow_initialize_from_backup = N'false', @enabled_for_p2p = N'false', @enabled_for_het_sub = N'false'

GO