Are there any tweaks for Lion's autocorrect?
For specific terms you find are getting "corrected" often, you could add them to the text substitution list as substitutes of themselves. That should work as a sort of whitelist to stop them from being autocorrected improperly.

Open up the Language &amp; Text panel in System Preferences, and on the Text tab, click the + to add a new substitution. Enter the word you want whitelisted into both fields.