iPhone / Mobile Device / Web Application Shared To-Do List

This is a web application geared to iPhone and other mobile devices using webkit. It's not a standalone iPhone app. This is a relatively simple app, just a simple TO-DO list. It should be able to nest goals into categories, or have goals that are steps in accomplishing larger goals. So, the goals should be able to be nested. They should be able to be assigned to multiple categories, and lumped into groups such as "goals for today", "goals for this week", etc. Another key feature, is that I need a user system that allows goals to be shared with other users. There might be a goal that one of a group of people can complete, and so that person can mark it complete when they finish it - and everyone who shares that goal can see that it has been completed. I'd like to start off there, create a simple but really nice and functional to-do list system. I have ideas to expand it as the user base grows. It is important in runs extremely fast and efficient. I will hose the web app on my own server, and would like it developed there so I know it's compatible with my server features. Therefore, I'd like the app to use the webapp library: [login to view URL] And, I'd like it backended with PHP and MySQL. The webapp pags will make AJAX calles to php scripts which will interact with the mysql database. Please take a look at webapp before bidding on project.