set default User Level to 4 (or x)

is it possible to set the user level for any newly registered user?
as the admin i don’t want to have to go through the trouble of setting newly registered users’ levels. instead, YES, i do want them to be able to post new entries right away (not talking about comments. i need newly registered users to get security level 4 right upon registration).

possible? if so, HOW?

thanks much!

pirco