and GlobalFoundries will demonstrate a 3GHz dual core Cortex-A9 made with their 28-nm processes sometime in 2012
It's a bit vague but I think they have already built this.
BTW the 32nm SOI process AMD uses appears to be faster so they could make them even faster...
ARM will be the only CPU architecture running on *everything* from phones to workstation/servers, with many interesting devices in between. 
Actually they go a lot lower already and will go higher than servers. I would say they're not in PCs but that's not true, you'll find several ARM cores in modern PCs - the HD has one, the WiFi, etc...
