“The trick is to use “Iframe Preserver” WP plugin (which is free). As the name suggests, “Iframe Preserver” plugin will “preserve” tags, but, it will also preserve any other HTML object (actually, any string what so ever).

“The stripping of tags is happening because native WP post publishing function is tripping them. However, there is a quick workaround.

Install this WP plugin http://wordpress.org/extend/plugins/iframe-preserver/. Displaying iframe/object tags will not be a problem. Here is how it works.

After the installation of “iframe-preserver”, edit post template and replace whole .. code with this:
[field name=iframe] — seem SAMPLE content at the bottom.

Now, add one custom field (under “Custom Fields” part of template) with name “iframe”, and the whole object code should be pasted in the value of the new field.

So, now, post doesn’t actually contain tag, but “iframe-preserver” plugin will replace text “[field name=iframe]” with the value of custom field whose name is the same as “name=” element in post text (this way, one can have multiple different iframes/objects in a single post). This works because fields are not filtered in the same way as post content."

SAMPLE content:

There’s a lot to learn about table tennis.  It is a game for all types of players.  This clip shows professional table tennis players.  What a game! 
 [field name=iframe]

Download this sample csv file: http://blogpig.com/images/CSVPiG_Demo02.csv