Yes, but if you have apps on your internal flash those will be unavailable as it will automaticly switch to Apps2SD.
By inserting a new MicroSD card with ext3 partitioned, will apps2sd automatically be enabled?
I solved this by running "a2sd remove" before partitioning my SD-card. Then do an "a2sd reinstall" after having booted up with a partitioned card in the phone. That worked for me. I'm running with my apps on a 512Mb EXT3 partition right now.