To filter a list by user ID, assuming you have a user element (or some other element that stores the user ID of the creator) called 'user_id', you would set up a pre-filter on either the menu's list settings, or the main list settings, as:
Field: user_id (raw)
Condition: EQUALS
Value: {$my->id}
Type: text
Apply to: Public
Note that if you set the prefilter on the menu, it can easily be bypassed by simply leaving off the Itemid from a link directly to the list, so menu prefilters should not be considered "secure" in any way. If you put the prefilter on the list itself, then all access to the list will be filtered.
-- hugh