It looks like Acer is the first to ship a Phenom Tri- core 8400 based machine. Austrian retailer Niedermeyer.at has Acer's Acer Aspire M3100 VYP machines, and it swears to ship them within 36 hours.
The machine comes with AMD's Triple-Core Phenom 8400 clocked at 2.1GHz, 3 GB DDR2 SDRAM, a 500 GB SATA hard disk and a Super Multi DVD.
The machine comes with a Radeon HD 2600 PRO HDMI graphics card with 256MB, and probably by some miracle, can address some additional 1018MB memory.
It also comes with Vista Home Premium, a mouse and a keyboard, and all this will cost you €599. We can bet it's faster than most dual-cores, and this is the goal of this machine.
You can see one and pre-order it here.