In general, Citi allows 2 applications every 65 days and the minimum wait time between cards for Chase should be 1 month since Chase is getting very strict on the number of cards you can have.

I would urge you to be very selective about the Chase cards which you can apply for. If you haven't already got the 2 Citi AA 75,000 mile offers, I'd suggest going for those.

I've written a few posts on credit card churning in my blog that may be helpful. If you apply and are denied, don't hesitate to call the reconsideration line.