If it's an MS Publisher file indeed (you seem to know) you need that program to open it. Your choice to do so or not do it and not open that file.
But maybe you can find a friend or relation that has the program and lets you use his PC to open it?
Kees
how do i open a .pub file? i dont want to buy ms publisher either!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic