You can make do with very little equipment for microstock photography, however if you have high quality software and camera equipment you will definitely have an advantage. 

 Basically all you need to get started in microstock photography is a camera, computer and an internet connection.  Having a fancy DSLR is an advantage, as is a fast computer, high quality photo editing software and a speedy internet connection.  At the same time however, you can make do with very little if you just was to try microstock photography out and see if it is for you.

Absolute Minimum Equipment
Camera: 3 MegaPixel Point and Shoot Camera
Computer:  Most any will do
Editing Software: Any free software will do
Internet Connection: Any connection

Recommended Minimum Equipment
Camera: Entry level DSLR with kit lens
Computer: Most any will do
Editing Software: Any free software will do
Internet Connection: High speed

Ideal Equipment
Camera: Professional DSLR or Consumer Model with kit or professional lens
Editing Software: Adobe Photoshop Elements
Computer: reasonably new computer
Internet: High speed

Professional Equipment
Camera: Professional DSLR and professional lens
Editing Software: Adobe Photoshop CS3
Computer: Fast computer
Internet: High speed