I put yesterday's unmask password plugin together with the code to automatically create a checkbox to control it, and removed the dependency on jQuery UI.
Example
<input type="password" id="password"/>
$('#password').showPassword('Show Characters as I Type');
Use
$('[type=password]').showPassword(string)
creates a checkbox as above with string
as the label. If the checkbox is checked then the password field is unmasked. $('type=password').showPassword(true)
unmasks the field directly, and $('type=password').showPassword(false)
restores masking.