The Pope is the Bishop of Rome. As a bishop, he is a leader of the Church and part of the teaching and guiding authority. He is also the Patriarch of the West, the head of the Roman church. He is also the Supreme Pontiff, the administrative and spiritual head of the entire Church on earth. On a lesser political matter he happens to be the monarch of the Vatican City in more recent times.
The Pope can call an ecumenical council, he chooses cardinals, he is the ultimate earthly authority in the Church. He is the supreme judge of Church laws and can alter canon law as he pleases.
The Pope's words are not by any means all directly from God. We do believe, however, that if a pope speaks officially and publicly on a matter of faith or morals in his role as the successor of Saint Peter and head of the Church, and what he says is to be held by all Catholics, then he cannot err because the Holy Spirit will not allow him to. Since a great deal of what the Pope teaches is either not binding on all Catholics because it is partially an opinion or view, this is rarely believed to have been enacted. Furthermore, everything that most popes say, if not an opinion, is usually already an official teaching of the Church, so Catholics believe it anyway.
We do not place the Pope's declarations, even the infallible ones, on the same level as Scripture. They are indeed inspired by the Holy Spirit, and inerrant, but Scripture is utterly unique in Catholic thought. It is breathed by the Holy Spirit and such that it is true in an incredibly profound way...every word is sacred. No-one would read through a Pope's encyclical in quite the same way as he would the Bible.
He's basically like the King in a monarchy. Much of his authorities are of course deferred to other people, but if he wishes he can have the final say.
Some of the Pope's titles reflect his role and position...he is the Supreme Pontiff, the Successor of Saint Peter and the Vicar (representative) of Christ.
I hope that helps a little and I wasn't just telling you things you already knew.