Jeri tweeted this address on July 7, 2013 as the one to send fan mail to. I imagine a SASE would still be appreciated if requesting an autograph.
Jeri Ryan, c/o ICM
10250 Constellation Blvd
LA, CA 90067-6209
USA (if mailing from outside of USA)
Http://www.jeri-ryan.net has been moved to a new server and it will take 24-72 hours for the new DNS resolve in your area. If the site appears down to you, this is the reason.