Guides
Below are a couple of guides to help you with your speedsailing.

Roo's Guides:
Choosing a GPS
Setting up a GT-11 (outdated 2007 version, see below)
Downloading and Analysing Data

Other guides:
Setting up a NAVI GT-11 (current in 2008)
Alpha racing

Software:
By replacing your DEFAULT.RSP file (in RealSpeed) you can calculate everything at once.
Here are two versions of the default.rsp file.
Basic (6 categories)
Advanced (Thanks Elmo!)