Hello,
First of all, congratulations on the effort you have put on the documentation wiki and the forums as well!
I have implemented postTo on my iframed application following the guide on the wiki (http://wiki.developer.myspace.com/index.php?title=How_to_access_JavaScript_libraries_from_an_IFrame). It works fine on Firefox and Safari, however on IE it seems to 'choke': the popup window appears, but when the user clicks on send, the window is still there. The recipient does get a message though, but the problem is for the sender, because since the window doesn't dissappear, a message gets sent for every click on 'Send'. Clicking on 'Cancel' doesn't get rid of the window neither, user has to reload the page.
Any help on this issue would be much appreciated.
Thank you!