While Apple is still quoting 4-6 week delivery times for new Mac Pro orders, those who need one sooner should know that Amazon has both stock configurations ready to ship immediately. The quad-core 3.7GHz Mac Pro with dual AMD FirePro D300 cards and 12GB RAM is $2,994, while the six-core 3.5GHz Mac Pro with dual AMD FirePro D500 cards and 16GB RAM is $3,994. You can find them here:
If you want more RAM, it's cheaper to buy it yourself from a place like OWC anyway (video tutorial after the jump.) Additionally, Amazon doesn't charge sales tax in most places, so at those high prices, you're saving a pretty penny. Overnight shipping on the Mac Pros is available as well.