Here are the steps broken down:

If you have Windows 7 and an external Stylus (like Bamboo Pen) or Tablet PC:

1) Use "Math Input Panel," located in Start->Accessories.  Right click on it in the menu and pin to your task bar if you expect to use it lots...This much will allow you to quickly hand-write and plop equations into MS Word.

If you want to be able to put these handwritten equations into Google Docs or webpages that require formats other than MathML, you will need MathType, which has a clipboard that automatically converts your equation into a desired format of your choice.   Here's how...

2) Inside MathType, choose Edit->Open Math Input Panel and create your equation.

3) Inside MathType, choose Preferences->Cut and Copy Preferences and select the format you need for the application you are pasting into.  For Google Docs, choose "Equation for application or website" and select "Google Docs."  For Desire2Learn, choose "Blackboard."  

Now you can hand-write, copy, and paste equations directly into browser-based authoring environments!

If you are interested in seeing a fuller survey of digital equation editing options, see this slideshare presentation.