wClock is a menu bar clock with date, time & calendar.
wClock displays the time and date in the menu bar and provides convenient one-click access to a monthly calendar. The format, font, and color of the menu-bar display and the starting day of the week in the calendar are fully configurable.
"If you find this application useful please consider making a donation."
[7/12/2006: The Wolfware site currently appears to be down, but I used it fairly recently. I'll link to a mirror in the comments.]