What is Comprehensive Income, how does it arise and how is it computed?

I would start with FAS #130, found here http://www.fasb.org/st/

There may be some prior discussion threads of value, such as
http://benefitslink.com/boards/index.php?showtopic=25697
http://benefitslink.com/boards/index.php?showtopic=21189
http://benefitslink.com/boards/index.php?showtopic=24248

Thanks but that only defines it as the change in net assets ... during the period arising from transactions/events from non-owner sources.

The comprehensive income from a DB plan will be part of the total comprehensive income defined above. The question is how would a DB plan create comprehensive income? I think I found the answer.

FAS 132, para 5c(5) says - Any intangible assets and the amount of accumulated other comprehnesive income recognized per per para 37 of FAS #87.

FAS 132, para 5i requires a disclosure of "... amount included within other compresensive income ... arising from a change in the additional minimum pension liability recognized per para 37 of FAS 87.."

The second sentence of para 37 of FAS 87 reads "If an additional liability required to be recognized exceeds the unrecognized prior service cost, the excess (......) shall be reported as separate component (that is, a reduction) of equity ........". Is this "accumulated other comprehensive income"?

From this I would say:

For FAS 132, para 5c(5), The accumulated other comprehensive income equals (the recognized additional liability minus unrecognized prior service cost), if greater than zero.

and

For FAS 132, para 5i, the compresensive income would be the change in the recognized additional minimum liability from last year.
Should this not be the change in accumulated comprehensive income?

Here are some hard numbers:
As of 12/31/03:
Additional Liab = 455k. Unrecognized prior service cost = 470k. Therefore, Accumulated other comprehensive income = 0 (because 450k < 470k) .

As of 12/31/04:
Additional Liab = 320k. Unrecognized prior service cost = 450k. Therefore, Accumulated other comprehensive income = 0 (because 320k < 450k) .

Is comprehensive income for 2004: -135k (=320k - 455k) or 0 (0 minus 0, accumulated income is zero for both years)?

You do not have AOCI for either 2003 or 2004, since your Unrec PSC exceeded your additional liability. As a result, you would not have any Other Comprehensive income from the pension plan for 2004.