Lee was the first company to use zippers in jeans in the 1920's and in the 50's it becomes quite common and all companies make a zippered version of their jeans. Levi's even made their iconic 501 with a zipper and named it 501z, as did Lee with their iconic 101, which they named 101z - the Z meaning Zipper.
This wasn't to everybody's satisfaction, as one Levi's customer noted that it was like peeing into the jaws of an alligator. This is quite understandable as zippers back then where all made of metal, not nylon and other softer materials that we see today. But it did catch on and became a huge succes for both men and women. Though to this day many of the hardcore denim fanatics would never wear jeans with zippers. The reason would most likely be the fact that a button fly can create some beautiful fades and if you are wearing shrink to fit denim, then the zipper might start bulging after shrinkage.
If you are into vintage jeans or reproduction jeans - basically premiuim jeans - then you should know the following makers.
Talon (Especially Talon 42)
Conmar/Conmatic (I'm not entirely sure that these have been used in jeans, but it is a great zipper no less)
Riri (only used in modern jeans, but a great quality zipper)