Express ShipStation

ShipStation is a web-based shipping solution that streamlines the order fulfillment process for your Magento store. ShipStation downloads your orders in real-time, allows you to create USPS and UPS shipping labels and packing slips in batch, and communicates tracking information to your customers.

Please Note: This is a free extension that allows you to easily launch ShipStation from the Magento Admin Panel. The ShipStation service starts at $25 per month and includes a free 30 day trial!
Print Shipping Labels and Packing Slips in Batch

Simply select the orders you want to ship, choose your shipping options, and voilà, you can print all of your shipping labels and packing slips in minutes! ShipStation is packed with features such as Automation Rules and Product Defaults that allow you to eliminate manual data entry.
Consolidate Orders from Multiple Channels

ShipStation not only supports your Magento store, but it also integrates with eBay, Amazon, Buy.com, and more! See our full list of integrations here.
No Software to Install

ShipStation is a web-based solution that is hosted in the cloud. This means that you never have to worry about installing software, upgrading, or backing up your data. Simply log into your account from any web browser to manage your orders, create shipping labels, and view reports. ShipStation works with both PCs and Macs!
Free DYMO Endicia Account

Each ShipStation subscription includes a free DYMO Endicia account which allows you to print all classes of postage for the US Postal Service. ShipStation also provides significant discounts on USPS Priority Mail.
Free Express 1 Account

Your ShipStation subscription also includes a free Express 1 account. Express 1 provides deep discounts on USPS Priority and Express Mail.
More Information

Here are some helpful links with additional information:

Magento Integration Overview
Multi-channel Integration
Batch Shipping
Benefits of a web-based shipping solution
Business rule automation
Managing returns in ShipStation
Full feature list
Pricing details
Contact Information

Email Sales
Email Support
Log into ShipStation