Welcome to Android Central! Are all other web services working normally on your phone? Can you access Google apps without difficulty, like Gmail, Google Calendar, etc.? If all Google services are slow or not connecting, there might be a temporary server problem. You could try going to the App Manager, selecting Google Play Store, and Clearing Cache/Clearing Data, then Force Stop. Now try again.
Does this happen only on your home wi-fi network, or on any? How about mobile data? If it's only on your home wi-fi, review this guide and see if any of the tips help:
http://forums.androidcentral.com/amb...-problems.html