From ABC News 

The United States Postal Service will announce a $2.5 billion dollar yearly loss tomorrow, ABCNews.com has learned.

But postal officials say it is unlikely to result in any increase in the cost of mailing a first class letter.

The price of a first-class stamp was raised one cent in May of this year, to 42 cents, following an even larger loss last year of $5.1 billion.

Postmaster General John E. Potter has said no further increase in the cost of first class stamps would be considered until May, 2009 at the earliest.