Like the "Allow SMF to collect..." option on the install. How would I, with PHP send information to another website. Sort of like calling a function, but it actually runs on and returns to a different website.
What do you mean? give a specific example with a site.
In general terms, you can pull data from a site and store it in a variable.
If your setup allows it, you can do something as simple as $site = file_get_contents('http://www.somesite.com');
To 'type into ' the other site, you can use CURL functions (google CURL,PHP)