By adding a top clause to your delete statement you can delete a chunk of records at a time. By combining it with a while you can put it in a loop and wipe the entire table.
WHILE
EXISTS (SELECT * FROM Foo)
BEGIN
DELETE TOP(100) FROM Foo
END
Had someone send me an email telling me that it might be better to use a TRUNCATE TABLE command then this method, and in most cases this is preferable. Conversly not always do us "evil" developers get TRUNCATE permissions from our DBA's. You can read more about TRUNCATE here (http://msdn2.microsoft.com/en-us/library/aa260621.aspx).