There is a number around, lots will simply set the date/time but as Paul Mac said there is a few about that will do extra things.
I used the James program for some time with the only problem being that it used up a bit to much memory for some of my progs, if you want to simply organise your boot up then you should use Super Boot (I think that is the name) it will also organise the auto folder and ACC programs if you want (this program eats disk space though).
RE: Time/Date setting