In Sql Server 2005, you can use the sp_startpublication_snapshot stored procedure to achieve this, using the following format:

sp_startpublication_snapshot [ @publication = ] 'publication'

[ , [ @publisher = ] 'publisher' ]

(omit the publisher out if you are using a SQL Server publisher).

I do not know if this is appropriate to Sql Server 7 or 2000 though.