I have found that "evangelizing" or preaching rarely works. As others have said, do it your way for your own code, make it known that you do it, but don't try to force others to do it. If people ask about it be supportive and helpful. Offer to do a few lunch-time seminars or informal dog and pony shows. That will do a lot more than just complaining to your manager or the other developers that you have a hard time writing tests for code they wrote.
Slow and steady - it is not going to change overnight.
Once I realized that at one place where I worked the acceptance for peer reviews improved tremendously. My group just did it and stopped trying to get others to do it. Eventually people started asking s about how we got some of the success we did. Then it was easier.
