You mentioned that your manager is on board with unit tests. If that's the case, then why isn't he (she) enforcing it? It isn't your job to get everybody else to follow along or to teach them and in fact, other developers will often resent you if you try to push it on them. In order to get your fellow developers to write unit tests, the manager has to emphasize it strongly. It might end up that part of that emphasis is education on unit test implementation which you might end up being the educator and that's great, but management of it is everything.
If you're in an environment where the group decides the style of implementation, then you have more of a say in how the group dynamic should be. If you are in that sort of environment and the group doesn't want to emphasize unit tests while you do, then maybe you're in the wrong group/company.
