I am currently developing a time management web app. I recently became convinced that my app would be barely useful w/o a mobile component. Now that's the area I don't know much about. I need to decide if the mobile component will be using a regular PDA or a smartphone/blackberry or just a regular cellphone with a browser. Another decision is whether or not to make this purely a microbrowser-based app, or to use J2ME or to code it to a particular mobile operating system. So my decision involves both marketing and technical considerations.
Can anyone point me in the right direction(s).