Q: How can I set up my AirPort Express as an access point?

http://www.apple.com/support/airport/basestations/

As far as an access point, it would depend on how you intend to connect it to your current Wi-Fi network. If your current wireless router is another Apple base station you can connect the Express to it either by wire or wireless and then configure it to either roam or extend.

As far as performing as a print server, you can connect your multi-function printer to the base station's USB port; however, the print server on the Express will only support the printing function of this type of printer. It will not support its other features: copying, scanning, or faxing.