iOS: Fillr's aim is pretty simple: take the grunt work out of having to enter and possibly re-enter your details on forms while on your iPhone.
Fillr is a free extension for Apple's Safari mobile browser that stores your most constantly-used forms data ready for use when you hit a form while browsing. Rather than tapping to select each field, you instead tap on the Fillr button in the extension pane and then select the information to go into the fields detected on your given page. All the personal data you put into Fillr is, as per its app description, stored locally within the app.
Fillr (Free) [iTunes App Store]