Stamps.com does not work on Macintosh....
Guess not. But this might be an option. From:
http://www.stamps.com/postage-online/faqs/#macCan Stamps.com work with the Mac?
At present, the Stamps.com program is designed for use with Windows operating systems only. Mac users can still use the Stamps.com program on Intel-based Macs (with Windows installed) or on Macs with PC emulation software. We are currently working to enable Mac users to benefit from the Stamps.com service as well.Mac compatible shipping software is available with Stamps.com built-in through one of our partners—TrueShip. Visit www.trueship.com for more information. Please bookmark this page as we will provide updates on any future Stamps.com Mac compatibility.
Stamps.com has just launched a new web-based version of our postage software. The web version now allows Mac users to easily print USPS-approved postage via a web broswer like Safari or Firefox, with no software download required.
Here are some of the features of Stamps.com for Mac users:
- Easily buy and print U.S. postage in minutes from your browser in just a few clicks
- Avoid returned mail: each address is verified against the USPS database
- Calculate exact postage using our USB-powered scale. Place letter or package on Stamps.com scale and exact weight is sent to web-based program.
- Eliminate trips to the Post Office. Access special services including certified mail, delivery confirmation, insurance and more
- Hide the postage value on shipping labels: great for ecommerce sellers looking to avoid S&H fee headaches
- Get discounts not available at the Post Office. Save up to 15% off Priority Mail, up to 21% off Express Mail and up to 8% on First Class Parcels.
Let me know if you have any questions.