It's not like the current 30-pin connector will cease to work.
I doubt it will have an immediate affect.
The old iPad will still work with thousands of accessories while one with the new connector will only be compatible with a handful of products (without an adaptor) when it's released.
I wouldn't worry about it.
i have an ipad 3. will it hurt resale value if they update ipads next month with this port?
if they dont update it then it will be updated more than likely next march for the new one. Whats everybodys take on it?
I'd be very surprised if this had any effect on resale other than just no longer being the newest version availabe.
It wouldn't hurt me, I've got three people lined up already asking to buy my iPad when I replace it.