As others say - don't get into specifics, if your concern is street and number, skip it - keep it to the city. If your concern is that they were in a certain city or town and have since moved - I recommend keeping the location you worked in.
Resume items are most useful as a way to reference your job history - the majority of readers of your resume are looking to get a sense of you and your job history. Keeping the location you actually worked at, lets the reader:
Scan his memory for anything he knows about that company and it's location - the business, the people working in it, anything about its reputation. Even in a city, the people in a given industry often know quite a bit about other employers of a similar skill set.
Shows your pattern of work - if you change the city each time the employer moves, you run the risk of giving the impression that you yourself have moved. What that means to the reader is anyone's guess - my only point is that it isn't accurate, and you don't want to try to explain that in an interview.
Assume consistency - after all, you're not going to remove a company when it goes out of business - so keep a consistent pattern. Also, this will keep you from having to launch an update every time there's a move.
If a company wishes to do a reference check, they will likely send you a more detailed form asking for location and contact points. That's the time to get accurate information to share. At that point, they will likely be calling and checking history, and so it helps to provide as much accuracy as possible in terms of finding the company.
In the meantime, you may encounter questions like "I didn't know that X company was in Y location..." - which are a great jumping off point for explanation. For example "Well, when I worked there there was Y location, it was a great site. I left when the business was waning, and eventually they had to disband Y location."
I've done similar, even when companies left my country entirely, and never had a problem with it.