hello,
i'm looking for online products that exist on the market that not only
test students and place them in appropriate remediation programms. but
also offer courses that help students to reach a certain level of
proficiency. i'm also interested in any form of statistics or report
that validates that a certain online course really helped the students
to become better in a certain topic (reading, writing or math for
example).

The one product I know of that tests students on skills is ACCUPLACER
offered by  the College Board of Education but that product doesn't
offer courses for students to enhance on skills:
http://www.collegeboard.com/highered/apr/accu/accu.html

There is PLATO: http://www.plato.com/ (but this seems to target pre-college level)

A recent announcement from SMARTTHINKING:
http://www.smarthinking.com/static/aboutUs/newsAndEvents/pressReleases/press63.cfm

Please send me any comments or questions.

Thanks for any help,

- Holger