XMp3: Everything you ever wanted to know
Pioneer has put up detailed images, specifications and the user guide for XM's upcoming portable satellite radio player, the XMp3. But rather than make you read the 78-page user guide, I've broken down all the highlights in one handy post. 
Aside from what we already know, the XMp3 seems little different from the Pioneer Inno... right? Not really. XM has added a myriad of new features that many Inno-users will be jealous over - though the lack of WiFi is a supreme disappointment. The Stiletto's WiFi functionality is a godsend for those who want to listen indoors, and I really wish the XMp3 had it included. But I digress.
Programming Guide:
The first killer upgrade is that the XMp3 will be the first XM radio to feature the electronic programming guide. You can see a list of programs that will be playing on a particular channel, then highlight a program and select it to see information about that program, schedule to record it, or set an alert that will notify you when the program starts.
XM Highlights:
For those times when you're looking for something to listen to, XM has (finally!) created a list of XM Highlights. You can pull up a list of the best programs across select XM channels for the next few days.
TuneSelect and Favorites:
Additional features include 30 TuneSelect options for notifications when your favorite artist or song is playing across the XM dial. The XMp3 also allows you to save up to 99 favorite channels (hopefully you won't need that many, since that sort of defeats the purpose).
Pause/Replay:
The XMp3 allows for pause and replay of live XM for up to 30 minutes. You can turn the wheel to see a list of songs that you missed, from newest to oldest, and skip to the previous or next song in the list. You can also rewind or fast-forward through individual songs.
Recording Features:
Thanks to the RIAA, there's been a bit of crippling of the XMp3 versus the Inno. The XMp3 allows for 75 hours of recording of "programs" and 10 hours of "songs" on the 2Gb of internal XM storage. But XM has done its best to make whatever capabilities are available into some pretty useful functionality. The XMp3 is also microSDHC compliant.
Auto-Recording:
Not only can you recording up to 5 channels at once, but the XMp3 radio also learns your listening habits and records those channels automatically. The XMp3 will save up to 30 hours of XM programming from the five channels you listen to most frequently, so it's effortless content for on-the-go.
Battery Life:
The removable Lithium-ion battery allows for 16.5 hours of playback time and 4 hours of live XM. That's a bit of a disappointment for those who listen to live XM a lot, but the 5-channel autorecording theoretically helps offset that.