Apple started selling its new Mac Pro today, with ship dates that start on December 30 in the US and January in other countries. There's also a ship-to-store option for Personal Pickup orders, but it looks like those units will arrive at the end of December as well.
The base model of the Mac Pro starts at US$2,999 for a machine with a 3.7 GHz quad-core Intel Xeon E5 processor, 12 GB DDR3 ECC memory, dual AMD FirePro D300 with 2 GB GDDR5 VRAM each and 256 GB of PCIe-based flash storage. The top model with a 12-core processor, 64 GB of RAM, 1 TB of PCIe storage and Dual AMD FirePro D700 GPUs (6 GB VRAM each) costs a whopping $9,599. You can check out all the configurations and ship times on Apple's website.
As noted by 9to5Mac, the Mac Pro is also available through third-party resellers. Though they can't ship the Mac Pro any faster than Apple, these retailers, like B&H and MacMall, may save you some cash. The biggest savings will be in taxes, with B&H only charging sales tax in NY and MacMall charging it in five states. MacMall also takes a $5 cut out of the base price of the machine.
Update: Ship dates for the Mac Pro are now pushed out to February in the US, UK and other countries worldwide.