If it's an EDU, such as facts.edu that you refer to in some past posts, then the following is of note to anyone who chooses to get involved with such a sale (you, buyer, broker, etc)...
Yes, older .EDU domains are "grandfathered" in, BUT such domains
still come with much restrictions; can still be revoked.
In particular, note the blurb in the 3rd item below regarding "generic" .edu domains (edit: that part may be ok for "grandfathered" domains regardless of affiliation / use)
http://www.educause.edu/edudomain/policy.asp
Amendment 6
On July 25, 2003, Amendment 6 [PDF* 143KB] to the Cooperative Agreement clarified and changed several important policies applicable to the .edu top-level domain:
Names in the .edu top-level domain, regardless of when issued, may not be transferred in any way by the Registrant to any other entity.
Transferring" includes selling, trading, leasing, assigning, or any other means of transferring.
Names in the .edu top-level domain that are not grandfathered must reasonably represent the name of the Registrant, may not be deployed to identify any organization other than the Registrant, and may not be "generic names."
Registrants in violation of these policies will be notified by EDUCAUSE in writing. Violations not corrected in 45 days will result in removal of the registration of the .edu name.
EDUCAUSE will conduct a six-month study of .edu names not in compliance with current policies and will make recommendations to the Department of Commerce with respect to bringing such registrations into compliance.
Ron