Archangel Gabriel

"The name Gabriel means "man of God," or "God has shown himself mighty." It appears first in the prophesies of Daniel in the Old Testament. The angel announced to Daniel the prophecy of the seventy weeks. His name also occurs in the apocryphal book of Henoch. He was the angel who appeared to Zachariah to announce the birth of St. John the Baptizer. Finally, he announced to Mary that she would bear a Son Who would be conceived of the Holy Spirit, Son of the Most High, and Saviour of the world. The feast day is September 29th. St. Gabriel is the patron of communications workers."

Gabriel is considered by many to be the greatest and most powerful of all the angels (except, of course, for Lucifer, who went bad). As the patron saint of communications workers, I suppose that means he's probably the patron saint of the Internet as well; at least he's someone for Catholic sysadmins to pray to.