From the NFL:

A total of 32 compensatory choices in the 2009 NFL Draft have been awarded to 16 teams, the NFL announced today.

Under terms of the NFL Collective Bargaining Agreement, a team losing more or better compensatory free agents than it acquires in the previous year is eligible to receive compensatory draft picks.

The number of picks a team receives equals the net loss of compensatory free agents up to a maximum of four.  The 32 compensatory choices announced today will supplement the 224 choices in the seven rounds of the 2009 NFL Draft (April 25-26).  This year, the compensatory picks will be positioned within the third through seventh rounds based on the value of the compensatory free agents lost.

Compensatory free agents are determined by a formula based on salary, playing time and postseason honors.  The formula was developed by the NFL Management Council.  Not every free agent lost or signed by a club is covered by this formula. 

One club this year (Arizona) will receive a compensatory pick even though it did not suffer a net loss of compensatory free agents last year.  Under the formula, the compensatory free agents Arizona lost were ranked higher than the ones it signed (by a specified point differential based upon salary and performance).

Thirty compensatory picks were awarded to clubs based upon the compensatory pick formula.  By rule, two additional choices were awarded at the end of the seventh round to bring the total number of compensatory selections to 32, equaling the number of NFL clubs.  The two additional picks were awarded to Detroit and Kansas City based upon the 2009 draft selection order.  (Note: St. Louis and Kansas City finished 2008 with identical records.  St. Louis chooses second in all odd rounds and Kansas City chooses second in all even rounds.  Once compensatory picks have been awarded according to the formula, draft selection order is followed to assign any remaining picks, and for this purpose, the assignment of the pick is made as if it were the eighth round, so Kansas City is awarded the choice.)

 The Seahawks get three picks in the seventh round -- 245th, 247th, and 248th overall. Hey, maybe they can draft a couple more kickers and really gum up the roster!

Here's how the formula works for Seattle:

 Colbert was sort of lost and signed at the same time, but there you go.