The UPS Store at 5 River Road (next to Tom-E-Toes Pizza in the Stop and Shop plaza) can arrange to have a package sent by UPS (800-742-5877) or FedEx (800-463-3339) or you can deal with them directly. E-mail: store; fax: 203-834-2037. The store offers mailbox and postal services.
And at the post office, of course, on may send packages (see above).