Try this add in: http://www.j-walk.com/ss/pup/pup6/index.htm free for
thirty days & well worth it for what you get.

The author of the program also writes fantastic excel books, more on
that he http://j-walk.com/ss/books/index.htm

There's also a date & time picker from Microsoft, but I can't find it
online. Check add-ins...