image map not working on iOS devices, with large images that get rescaled by the device

This topic was solved here on stackoverflow: jquery-image-map-alternative

The best idea is to use absolutely positioned anchors (also as suggested by steveax) instead of imagemap.

Update

As this is an old question, you might consider using SVG maps these days. They are supported in all modern browsers, works responsively and are as easy to use as image maps. (thanks to user vladkras for reminder)

Why don't you use Responsive Image Maps instead. This way you can still use poly maps for oddly shaped items.

http://mattstow.com/experiment/responsive-image-maps/rwd-image-maps.html

It's as easy as adding the script. And one line of javascript:

$('img[usemap]').rwdImageMaps();

Nathan's comment is correct. You need to fix the viewport to prevent scaling. Basically, either specify a fixed pixel width, or set the scale to 1.0 and set user-scalable=no

See this document for reference:

http://developer.apple.com/library/ios/#DOCUMENTATION/AppleApplications/Reference/SafariWebContent/UsingtheViewport/UsingtheViewport.html

An alternative to using the area tag is to use javascript with events x/y & bounds for your hit areas.