I've posted a couple of times on the REDFLY Mobile Companion device (here and here) and was very impressed with the build quality, ease-of-use, and functionality of the device during my evaluation period. I sent the device back a couple weeks after I received it to for evaluation and have been considering a purchase upon availability.
I recently found out that you can now pre-order the REDFLY that should start shipping very soon, if not already. These initial units are labeled REDFLY evaluation/demo unit pre-orders and by placing an order you agree to be contacted by Celio to qualify the sales opportunity. This sounds like they may have a limited initial availability and want to make sure you have a compatible Windows Mobile device to actually use the Mobile Companion. As initially stated at CES, the REDFLY Mobile Companion will be available for US$499. There are 5 and 10 unit packs, but the pricing remains the same.
I also just found out that Celio announced they are updating the driver for Windows Mobile 6.1 and will be supporting several more Windows Mobile devices.
I have a Fujitsu U810 UMPC that I was thinking about selling to buy the REDFLY unit, but I really do like the long battery life, Tablet PC functionality, and ultra mobile aspect (weighs just 1.5 pounds) of the Fujitsu U810. The small keyboard limits my writing a bit and the REDFLY solves that issue with its wonderful keyboard that I really enjoyed using (same size as the Asus EeePC). The REDFLY weighs 2 pounds and has a battery life of about 8 hours. I always have a mobile phone with me so the REDFLY would always have a companion in my bag. If I knew for sure that Celio Corporation would eventually release drivers for S60 or the iPhone then I would have no hesitancy at all in buying the REDFLY.
After laying it all out, I decided to get rid of a couple devices that aren't seeing much use (BlackBerry Pearl and Dell Axim X51v to start with) to build up my mobile device fund and just ordered a REDFLY for myself. I look forward to using the release version and latest driver software with the T-Mobile Shadow and HTC Advantage (both devices I tested with the earlier beta) and you never know, my Fujitsu U810 may be up on ebay soon afterwards too.