The right place to look for updates on Flex is http://flex.apache.org
The good thing is that activities are still going on. The bad things are that:
- Unless the dependency to Adobe air is cut, Flex as an open source project is bound to fail imho. See FlexJS for updates on that point
- Current activties seem to be focused around making things more polished rather than working on hard stuff (typically developing an independent and open source runtime execution engine => flexJS)
For a small company, home development, not so business critical applications, I recommend warmly Flex, since it is one of the best (if not the best) cross-platform mobile development environment (Very good performances if used appropriately, very good programming environment, lots of components, structured language, lots of documentation and tutorials, easy to design, etc.)
for business critical applications... The risk is high !