I think the Strongarm/Xscale-powered pda's have enough compute power to do psk31 without a dedicated dsp. Question is how many of them give you a clean path to the a/d converters in both directions. Lots of them have clean headphone output (so you can listen to music) but only have built-in microphones (for voice input) with no place to plug in an external audio source. I do think PSK31 should be built into radios, especially those radios that already have DSP's. Maybe VOIP programs will create some demand for pda's to accept headset mics. Finally, PSK31 (to me) is more interesting on hf than vhf, because hf's long range capability makes it useful for remote areas. For situations like Katrina, where a few dozen miles is enough range, higher speed VHF packet and digipeaters are likely to be much more useful than PSK31.