The mylo is a nifty little device that does wifi, Skype (you can hold it up to your ear or use a headset), GTalk (no voice), and Yahoo Instant Messenger. It also has a browser (Opera, no flash), has a photo album, plays mp3 and Windows Media Player music, and plays video formatted in the weird mp4 video format that the PSP uses. (I think. I have yet to successfully convert and play a video file.) I used it for Skype on a conference call today and it worked really well with Skype-Out. For some reason I don't see my contacts list on Skype. The other IM clients seem to work fine (GTalk and Yahoo IM).
The audio and video playback is good. The screen is a bit small but very clear. The device has a speaker on the back which is not stereo, but makes up for it in sound quality. In a relatively quiet room, playing music on speaker works well - much better than most cell phones designed for this kind of use.
It is rumored to be running some flavor of Linux inside. It mounts on your system via USB, but doesn't have bluetooth. It has wifi, but no GSM/GPRS. Definitely a downside, but an interesting twist after using the Sidekick for so long that has GPRS but no wifi. It also doesn't have email. It has about a gig of memory, but you can buy a 4 gig memory stick Pro Duo.
Overall I like it so far. The keyboard is a bit hard to use, but maybe it just takes getting used to. I like the way it flips out. The size is great. It is about the size of a largish cell phone, but much more pocketable than a PSP, DS Lite or Sidekick 3. I wish it had AIM and MS Messenger too, but I can live with Gtalk/Skype/Y!. The media playback is nice, but I wish it were more format friendly on the video. The interface is pretty fast and nice. The industrial design is pretty cool. The white bands glow in different colors for different states. When you are peer-to-peer wifi'ing, it glows orange. When you are connected to the Net in infrastructure mode, it is blue.
I'll post more updates after I play for it some more, but thought I should post this before everyone else got one and diminished the amount of envy I could muster with this post. I was able to get ahold of one though a secret source at Sony who I am not allowed to disclose. And before you ask me if I can get you one, I can't. You can pre-order them on Amazon.com for $349.99.