President Bush announces the annual National Day of Prayer here.  The day will be celebrated on May 3rd this year.  An interesting history of the tradition is contained in former President George H. W. Bush’s 1989 proclamation:

Since the approval of the joint resolution of the Congress on April 17, 1952, calling for the designation of a specific day to be set aside each year as a National Day of Prayer, recognition of such a day has become a cherished annual event. Each President since then has proclaimed a National Day of Prayer annually under the authority of that resolution, continuing a tradition that actually dates back to the Continental Congress, which issued the first official proclamation for a National Day of Prayer on July 12, 1775. By Public Law 100-307, the first Thursday in May of each year has been set aside as a National Day of Prayer.