Digitrax has just officially announced their first entry into the sound decoder market today in a release to all dealers. The unit is a PNP for the HO Kato AC4400, SD38-2 and F40PH. Here are exerpts from their release:

Announcing!
Shipping October 1, 2005

SDH104K1 SoundFX™ and LocoMotion® Decoder
This exciting new one amp mobile decoder from Digitrax has all the great LocoMotion® features you’ve come to expect and SoundFX™, too! Based on proven locomotive decoder technology, the addition of downloadable sound will simply “blow you away”! Ready to run with pre-loaded sounds or customizable with your own recordings. Supports the playable whistle feature with F2 key on DT400 throttles. Includes 28mm speaker. Plug N’ Play for Kato HO AC4400, SD38-2 & F40PH.
List $64.98, Tony's

FN04K1 4 Function Decoder
This new function decoder is a stand-alone function decoder that is also the perfect complement to the SDH104K1 SoundFX™ and LocoMotion® Decoder. 4 functions with selectable outputs. Separating the light function decoder from the sound and motor control decoder allows more flexibility and options for setting up lighting in the shell of the locomotive.
List $24.98, Tony's

SDH 104K1 & FN04K1 Combo Pack
This combo pack gives you everything you need to have realistic operation, sound, and lighting in your locos. Install the FN04K1 on your SDH104K1 before installing in your locomotive and you’ll have SoundFX™, LocoMotion® and Functions!
MSRP $79.98, Tony's