What are presets?
Lightroom presets can be your most powerful ally in making your workflow travel at the speed of light. While most of the time "presets" means Develop Presets, these saved settings fall under the following categories:
Where are my presets stored?
Where can I learn more about presets?
Here are some additional resouces to get you flying:
Use and Create Presets
Adobe TV - Adobe Lightroom 3: Presets and Templates
Adobe TV - QuickTip: Presets
Adobe TV - How to Migrate LR to Another Computer
External - Pretty Presets
Community Exchange - Lightroom Develop Presets