This would be the first of the Assiti Shards series or the 1632 series or whatever you want to call it! And it's by Eric Flint.
I've looked at this one I don't know how many times and thought "I should read that, I bet I'd like it." And now that I've finally done so... I did indeed like it a lot! It has a similar feel to S.M. Stirling's Dies the Fire series. Except instead of everything not working, it's an entire town that gets sent back in time. So the rules of physics haven't changed, but everything outside this one town has. So even though stuff works, there aren't going to be replacement parts coming, power is going to have to be generated somehow, and the people aren't exactly going to behave like we're all used to!
I did end up finding myself on wikipedia every other chapter or so because real historical people kept showing up and I wanted to know who they were and what actually happened. So I've learned things about the King of Norway and the war that was going on at the time and all kinds of interesting things!
Just like Dies the Fire this one had me doing the "what would I do?" thing while I was reading it. And even though stuff would still work in this universe, it freaked me out a bit more than Stirling's. I think it's the idea that there is absolutely nothing familiar left outside of your one little town.
It's an incredibly interesting book and idea and I'm very much looking forward to reading more in the series. I really liked watching the "natives" learn about American style democracy and equality and justice and all these ideas that we very much take for granted, but at that time would have been completely foreign and unthinkable.
And how do you prepare yourself for everything to break down? The modern technology is great and gives a huge advantage, but only for as long as it lasts. Sure, you could figure out how to make some things, but there'd be no way to make so many of the things that would eventually quit working.
So... very interesting and good book. Lots to think about, and I learned some history stuff that I never would have otherwise!