gAttach!  allows you to easily attach files to new messages in Gmail or Google Apps Mail.

All the features available in Windows that were once only available to your desktop mail-using friends are now available to all Gmail users.

Website: http://www.gattach.net/index.html

Dashwire is a free mobile phone contact, photo, video, and text messaging tool. It works on phones running Windows Mobile and symbian OS. It syncs your phones contents to the web and allows you to manipulate the data via a web browser.

I use Dashwire often to answer text messages because I can use the computer keyboard instead of the phone text input – which for me is quicker. I can also update contacts via the web interface with ease.

Other features I use is the ability to view, save, and forward pictures that I take with my phone.

Other things you can do with Dashwire includes seeing a list of all of your conversations (text messages), change the phone ringtone, set up speeddial for your phone, update your Dashwire, Facebook, and / or Twitter status, manage your mobile internet bookmarks, and manage videos you take with your phone.

The best thing is that Dashwire is free. 

The only downside to Dashwire (at least on a Windows Mobile device) is that it speeds up battery consumption. This is in part because it is in constant contact with dashwire.com so that the phone and the web site are in sync.