The easy way would be embedding it in an iframe on the page. Otherwise, build the form on the page, and use some jquery to submit the form using ajax.

There's exec-php that will let you embed PHP in your wordpress pages also, if that helps.

Hi There
I would do as 'bheadrick' suggests and use an iFrame.
You can use a plugin for adding php code and indeed iFrames called: 'Global Content Blocks' available here:
WordPress › Global Content Blocks « WordPress Plugins

The only thing I would add is that you need to make sure that the template you use has a full-width (single column) option and it is wide enough so that when you embed your iFrame you don't have any horizontal scrolling.

All the best
Kevin

I use WP Simple Insert - Bhaskar Kandiyal when it comes to simple codes.

But the better way is to write a shortcode { } and train the editor to include that code whenever they want.