If you use Outlook 2007 or newer, you can easily send SMS and MMS via SMSmidlet.com. Fast and without any installation!
1. In Outlook click Accounts settings and choose New - Text Messaging (Outlook Mobile Service)
2. Fill Service provider URL, username and password for SMSmidlet.
Service provider URL:
https://smsmidlet.com/post3/
3. After you save settings, restart outlook. After restart you can see new items in menu - "Text message" a "Multimedia message".