One of the great things about having remember the milk on the iPhone is portability. You have access to your tasks anywhere with the wonderful official iphone app but it doesn’t have tight integration with mobile specific tasks like call or sms or email someone right? Not quite.
The trick is to use custom url schemes. You can add tasks to RTM with the url set as a custom url scheme and it will launch the designated app. With the quick add task syntax, it would be like:
call for appointment tel://5559898
text bob sms://5559898
Those custom urls can be clicked from the task’s url field and will launch the designated application. Unfortunately, mailto: doesn’t work too well (you get “mailto” prepended the address) but for calls and text it works great.