For a MacBook (not Pro), I ordered the base model on Monday, with 1GB RAM and upgraded to a 120GB HDD, fairly simple really, and it's now Friday here and it's on it's way (as of Wednesday). I assume it'll get to me Today or Saturday. That should give you a rough idea.
For the MacBook Pro, standard configuration, it should take whatever length of time is advertised on the online store, which is probably overnight or 1-2 days. I haven't checked.