I would like to be able to add content to my K2 site through my iPhone or Blackberry.The iFrame doesn't allow me to scroll to the "save" button, so I am stuck.  Thanks.

this would be awsome!

also want

I remember seeing a post on Simon's old site that said - "posted from my blackberry" or something like that...it may still be on simon.getk2.org, not sure.
if you used a mobile template designed for smartphones for a specific menu choice shown to you only after logging in, it may help usability...

there is adminpad for administrator templates by pixelpraise.

its quite powerful and works with ipad/iphone. they even offer a free wyisywg editor ready for iphone/ipad.

i do not work for forementioned company. read more here: www.adminpraise.com/blog/team/adminpad-joomla-ipad-admin-on-the-way.php

this is for backend submissions of course