The Mono project recently updated their 1.0 roadmap and put dates on it. June 30th is the target date for the 1.0 release. It will be interesting to see if many managed apps for Linux start appearing after that point. I know my web log stats engine runs (slowly) on Mono, but I think the biggest potential for success is if Mono can run ASP.NET apps without modification. End users don't care what operating system the webserver is running and all the UI is already written in cross-platform language - HTML.