Unfortunately, Little Snitch does not completely block the spyware in CS3. There's a big thread about it on the LS forums. Some people were accusing LS of cooperating with Adobe by not blocking this spyware, but it turns out to have a technical reason. Part of the spyware runs as a root process and thus has higher privileges than LS. In fact LS doesn't even SEE it communicating at all, but if you check your internet traffic on your router or use an ethernet sniffer, you can see what data this spyware is sending back and forth constantly. Very disturbing and disappointing of Adobe...
Edit: I should clarify that there is more than one spyware program installed by Adobe CS3. LS can block some parts of it (the CS3 phone home stuff), but doesn't even see other parts of it. I believe the root process that bypasses LS is called "FLEXnet Publisher" and can be found in /Library/Application Support if Adobe CS3 is installed.