Stamps.com 

Stamps.com is an application that allows you to print your own postage stamps for US Mail, at 80% off the price you would have to pay if you purchased them directly at a post office.

The program itself can be downloaded and installed for free, but it requires that you are registered with your credit card as well as the information about your place of residence within the United States in order to function. Each time you use it, the program will connect to the Stamps.com servers, and your account will be billed accordingly after every stamp purchase. Besides acquiring stamps, the program's features also allow you to print postage and mailing addresses directly on envelopes, as well as shipping labels for parcels and postage for international mail.

One of the many advantages of Stamps.com is that it can integrate your already installed address-book software (such as Lotus Notes) and extract address information from it. Moreover, it can also integrate image editing programs (such as Corel Draw) to prepare the postage for printing.

In conclusion, Stamps.com is a useful piece of software, as it allows you 20% cheaper mailing. The fact that it can integrate address book and image editing software also makes it very easy to use.