[TYPO3] create "lightweight extension" (simple php app)

[Felix Natter]

hi,

I'd like to integrate a basic web application into typo3,
but don't really have time to learn how to write an extension.

Sometime ago there was an extension page_php_content, which allows
to insert php code, but it seems it's no longer available.

Even with such an extension, what is a good way to pass data from
one form (=typo3 page) to another typo3 page (i.e. in one form you
enter details and in the target page it will be written to db)?
Can I just use POST as usual?

thanks!

-- 
Felix Natter