Express Card is the PCI-Express-based replacement for PCMCIA (aka People Can't Memorise Computer Industry Acronyms). However, we've seen very little hardware actually make use of the slot. Dubbed the X-Fi Xtreme Audio Notebook, Creative's new buddy basically provides the same functionality as a desktop X-Fi card, with high quality processing and digital and analogue audio outs, and you can also choose to pick up an additional breakout box for full 7.1 speaker connectivity.
All the usual X-Fi features are included, such as the Crystalizer for cleaning up MP3 files and the various 'modes' for gaming, movie etc. What's not included is the RAM that you'll find on the Fatal1ty gamer board, which can increase framerate in sound-heavy gaming situations.
Creative has drives for Windows Vista included, but beware - the card itself isn't HDCP compliant, so you won't get the full audio quality out of the SPDIF port when watching HD movies. Indeed, the Creative website points out that the specifications are "24-bit/96kHz (Windows XP) // 24-bit/48kHz (Windows Vista)". Pay more, get less, good stuff.
It's not quite available to buy in Europe or the US yet, with the Japanese the only market to get the card so far, but expect a price in the £100 range in the next week or so. µ