I installed simulsays too on my ATT pearl and on sat. I did not receive any messages. Then today I restarted the app, one of the options after you open it, and the messages were downloaded.

A couple of items to note:
1) Max message length is 1 minute.
2) When you delete the message from the phone it does not delete off the Simulsays server

It will be good one day. Again, it is free so it is hard to complain.