Is there a palm app that would answer the incoming call and let the caller leave a voice message on my phone directly?

Call Answer - Turns out that Samsung T-300's have built-in digital answering machine capability. The feature is called "call answer" in the VoiceRec menu. Activate it, and whenever someone calls the phone will pick up and play back a greeting asking the caller to leave a message. You have the option to pick up the phone even when the caller already has started leaving message by pressing "Send" on the keypad. You also get the benefit of being able to screen callers this way - you can listen to the person start leaving a message, and if it's someone worth talking to you may pick up.

That phone has it but you can't change the greeting and its only 10 seconds (3 rings)