Software for creating lighting plans/diagrams?

I'd like to share lighting plans with my crew -- what software exists for creating lighting plans? What are the pros/cons to the different packages?

I've been using Microsoft Visio, but there must be a better app for this.

Answer

Sylights (free registration required): http://www.sylights.com/

OLDC (free, with donation requirements for commercial use): http://www.lightingdiagrams.com/

Photo Diagrams (free, Flash-based): http://www.professionalsnapshots.com/PhotoDiagram/

Strobox (iPhone app, free): http://app.strobox.com/