When converting from a Flash CS3/4-based project, to a Flex-based project, there are not just one or two conversion paths to consider, there are many, all of which depends on the Flash project in question.
I’m on a discussion on LinkedIn, in which one guy asks if we know anyone who can do a Flash-to-Flex conversion project, which evolved into a discussion on techniques. Rather than post a pages-long reply, I thought I’d post it here instead:
First, for any Flash-to-Flex conversion to go smoothly, you’ll need at least one person on your team with a good dose of real-world experience with both Flash and Flex-based RIA projects (Flash banners do not qualify ;)), to guide the conversion process and make sure the best deployment strategies are implemented.
As far as the conversion path, there are several possibilities. Depending on the kind of project, you may want to migrate some, most or all of the project to Flex. When migrating from Flash to Flex, you’re not just migrating code, you’re migrating from a visual asset instantiation and state management environment to a purely coding-based methodology (if we forget for a second about Design View in Flex Builder).