I use Gmail so much now that in many ways, I prefer it to even using Outlook. However, integration with Windows is nowhere near as good as Microsoft Outlook for obvious reasons.

gAttach! bridges that gap somewhat by allowing you to attach files directly to Gmail or Google Apps Mail directly from Windows. In other words, just right click on a file, select "Send To" and "Mail recipient" and the plugin will automatically open your Gmail client with the file already attached. It not only attaches files directly from Windows Explorer - it also opens up a whole new world of attachment possibilities from Microsoft Office, Adobe Acrobat, Windows Live Photo Gallery, Internet Explorer and Mozilla Firefox.

There's not much more too it than that - it integrates perfectly into Windows Explorer. However, you may experience some glitches. If you are sending a file attachment whose filename is in a different alphabet to the one you use normally (e.g. your computer uses English but you're sending a Spanish attachment), it may not recognize or attach the file. It's also limited by Gmail's 20MB file attachment restriction. If you're logged into your Gmail, it won't prompt you for your details but if you are not, then it does ask you for your username and password which you may or not feel comfortable submitting.

For any Gmail fan, this is an excellent utility that makes attaching and sending files so much easier than opening your web client all the time.