I wondered, did you find it difficult to handle some people in winning them over to this?

For the people in my team, I had no difficulties whatsoever because I could sit with them and show them how to do it (as adrianh notes below: "show not tell").

For people in other teams, it depended on their interest and aptitude: some really surprised me by writing excellent unit tests without any prodding at all; others didn't seem to get it; others complained that they didn't have the time. Nobody said it was a stupid idea, the most common reason for not doing it was "I have a hard deadline and I just don't have the time right now, maybe I'll try it on my next project".

How did that change over time?

It's been over a year now, and TDD is growing slowly but steadily as the early adopters spread the word and show others how to do it. There are a certain percentage of programmers (maybe more than half) that don't read or study anything outside of work; the only way to reach them is to sit with them and show them how to do it.