Are there any good books or websites on this subject covering subjects like:
We have a rather large winforms based product which we would like to migrate to the web. Migrating in a 'big bang' scenario would probably take at least two years. We're looking for alternative scenario's. I'm especially looking for ways to handle the inbetween scenario, what options do you have to keep customers happy.
Based on our own experience with moving applications from desktop to web: carefuly inspect the architecture of your winforms applications and if possible - try to provide a web interface at the service or persistence level so that your windows applications use web services instead of directly talking to the database. Then you can let your users launch desktop modules from the application server using clickonce.
Such approach let us move to web quickly and users got the same GUI and a new way to access the application. In fact, it took like 3 or 4 months to redesign existing applications so that they use web services.
Then, we were replacing modules one by one, implementing them as web applications and maintaining both (clickonce and web) for a short period of time so that users were able to get used to new modules.
The migration of consecutive modules from clickonce to web was prioritized in an obvious way - we've started from modules that were used by most users. In fact, the initial release of the system has only one web forms module ready and remaining modules are being replaced for over 2 years now, one by one.