Someone asked me yesterday what should they do. How can they plan for the inevitable changes they’ll be making to their web map services. A good solution might be Mapstraction. It’s a programming library that allows you to easily switch between web map providers without having to change much if any of your code.
By avoid dependency on any specific mapping provider (or versions within a provider) your code is easier to maintain.
A book I reviewed about a year ago, Map Scripting 101, is a great starter for those who want to read up on Mapstraction. I mentioned that Mapstraction might be a good choice for beginners, but I think with the uncertainty of licensing and costs with web mapping APIs, Mapstraction might be a good choice for anyone.