Twitter and OAuth

I had a Twitter script that worked just fine allowing me to post directly to my Twitter account.

Now with OAuth coming in that has stopped.

Are there are simple instructions on how to use OAuth with PHP to connect to Twitter?

Unfortunately the library that is linked to most TwitterOAuth does not seem to work with older versions of PHP (before 5.2) and I can't get my host to update it, so that library I can't use.

Does anyone have any other solution for how to do connect to Twitter with oauth through PHP?