Embed video?

I want to embed videos in posts. I like the way "Simple Video Embedder 2.2 (James Lao) works straight from the post page, but I have to edit your code to make it work (directions below). I'm not understanding which file the code goes in, nor do I relish altering your code. Please advise -- or can you suggest a video embedder that works well with Atahualpa?

Simple Video Embedder directions:

In order to show the videos, the p75GetVideo() function needs to be inserted somewhere in the loop of your theme. The function has the following prototype:
string p75GetVideo(int $post_id)

This function returns the embed code of the video for the post with ID $post_id. Note that it does not print out the embed code but returns it as a string that you must echo. There is also a function that checks whether there is a video for some post.
bool p75HasVideo(int $post_id)

This function returns true if the post with ID $post_id has a video and false otherwise. I suggest you use p75HasVideo() to check for a video, and only get the video with p75GetVideo() if it returns true.

Something similar to this should go in the main loop of your theme:
if ( p75HasVideo($post->ID) ) {
echo p75GetVideo($post->ID);
}