This is a two part, related question:
I would like to know the number of alumni, and the alumni association
dues, for these universities :
harvard, yale, dartmouth, columbia, duke, USC, stanford, Univ of
Texas, Univ of Michigan, Florida State, Univ of Washington, Univ of
Chicago, Nebraska, Okla Univ, Beloit (in wisconsin) and Middlebury.

Additionally, i'd like to know what kinds of third party companies are
providing software and services to those universities listed above to
support their alumni organizations.

Just to get the ball rolling, the German Wikipedia site for Harvard
says that there were 270,000 alumni/ae in 2004, and about 20,000
active students.

http://de.wikipedia.org/wiki/Harvard-Universit%C3%A4t

You can probably make a fair estimate of the numbers for other
universities by multiplying the number of present students by the same
ratio: 13.5  - less for universities that have expanded considerably
in recent years.  The mix of students graduating from 1, 2, 3 and 4
year programs and those getting a second degree probably averages out.
 Some universities consider anyone who completed one term successfully
to be an alumnus/a.
I doubt that any alumni association charges dues  - Harvard's does
not.  The machinery of collecting dues would be immense, and negative
impact of cancelling membership would defeat the purpose of alumni
associations, namely, to maintain continuing interest and support for
the university.  They accept the costs of alum mags, etc. to maintain
contact for fund raising.
Hope this is of some help.