Include It is an old plugin that lets to include an external file in a post or in a page. It’s main usage is to include code that cannot be edited safely with the WordPress editor but you should use the new Include Me.
Include it can include a PHP page executing it, so it can be used to include external functions in your blog. In my case, I used it many time to embed in blog pages calculators or other small services I wrote with PHP.
There is anew version of Include it, called Inclide me, that I develope to use the short code available with WordPress 2.5. I had not time to submit to WordPress repository that plugin, I hope to find the time to add it ASAP.
Include it can include a external web page with an IFRAME too. This function was added because who use the visual editor cannot add IFRAMEs safely, they will be corrupted when the document is reopened.
The plugin can be found here.
There are number of examples on the plugin options page. Just install it (doesn’t hurt) and look at that page. Thank you.