Although I argued that a jailbreak release today made more sense, since a 12:00 PM Eastern release was more timely for international users, one of the side effects is that jailbreak package manager Cydia is currently overloaded due to very high traffic.
For the past few hours, users with freshly jailbroken iOS devices have been experiencing difficulties in using Cydia. The packager has been very slow to use for some, and isn’t functioning whatsoever for others. Cydia is simply buckling as so many users try to access it at once.
Our best advice is to exercise patience. Once the initial jailbreak launch period passes, things will get back to normal. Cydia founder Jay Freeman (saurik) puts a lot of time resources into the package manager, so I imagine that he will be working hard to get Cydia running at its usual performance.