T-Mobile has dropped the price of Sidekick Sync down to $2.99 a month. If you already bought Sidekick Sync you should go into the Catalog and upgrade in order to get the lower monthly price.
What is Sidekick Sync?
Sidekick Sync provides secure access to your Exchange Active Sync (Outlook) e-mail. calendar events, corporate directory and contacts on your Sidekick LX 2009. Read, reply and forward your e-mail, and accept calendar invitations just as you would on your PC.