This has been rumored for a while now with his declining health, but now there's an official announcement. All con "retirements" are subject to change of course, but between his age, health, and travel required, this is probably legit:
Jeremy Bulloch retires from conventions
Re: Jeremy Bulloch retires from conventions
Stan Lee also announced he's not signing in public anymore. I guess if he shows up, it's the Tim Curry approach, send in and photo ops only.
The Paunch Stevenson Show pop culture podcast : http://www.paunchstevenson.com