The Cisco 10GBASE-T Module supports link lengths of up to 100m on CAT6A or CAT7 copper cable.
Unfortunately, while the compatibility guide lists this new transciever, it doesn't indicate that it's supported by any current switches.
As far as I'm aware, this module is the 4th 10GBASE-T device in Cisco's lineup, having been preceeded by:
- 6716/6816-10T card for the 6500 (these are the same card with different DFCs)
- 4908-10G-RJ45 half-card for the 4900M
- 2232TM Fabric Extender
I'm not too excited about 10GBASE-T connections (and Greg Ferro hates them!), but I've seen a couple of use cases where having just a single port or two on a stackable switch would have been helpful.
It'll be interesting to see how these get deployed. A 10GBASE-T SFP+ module would be much more helpful these days, but I suspect that power, packaging or both are standing in the way of a 10gigabit version of the GLC-T.
Update 11/30/2011 -- I missed a 10GBASE-T offering (or maybe it just appeared). There's also the C3KX-NM-10GT, a dual-port 10GBASE-T network module for the 3560-X and 3750-X switches.