Adding mobile capabilities would be a game changer for me. I'd sign-up for a year and pay you for it if you built a mobile interface and/or sms interface. I'd be willing to pay $10/month if this made scheduling my life as easy as it looks like it could and it included all the free SMS I wanted to send for use in scheduling tasks via mobile.

A phone version is planned - but we've discovered that most phone browsers are really terrible. Are you looking for an iPhone web version, or for a jar version (like google did for gmail/google maps)? Or do you think something that uses Opera Mobile/Mini would be good enough?

It's pretty hard to get reliable worldwide sms delivery, but -- sms for the USA and Europe we can do, I think.

Just for another data point. I purchased the $25 Remember the milk subscription just so I could get the iPhone access. If you made this work with the iPhone I think you will create market share.

Maybe you could make it free for people unless they want the advanced features. The features could be sms/email notifications, more projects than x at a time, or whatever you might deem worth charging for. You will need to tweak the business model but so far the site looks clean and usable. Good job.

An iPhone interface and/or a generic smart phone interface (Android, WinMo, etc). Forget the lower end phones that don't support CSS, they aren't going to be in your demographic anyway.

A lot of times you can get away with a decent smart phone interface and just put a few meta tags in the head tag for the iPhone so that it looks slick for the iPhone too.

iPhone is fine since I have an Android.

Also choosing your own colors for projects would be nice :)