[kh99]

You could use a plugin, and use hook location global_start or init_startup. The right hook might depend on exactly what you need to do, but you could try those to start. If you do that, that script will be included on every vbulletin request. That might add a lot of overhead depending on what happens in that script. You might instead want to just use an "include_once" wherever you need to use the api.