The Acer Aspire One umpc is now available in US. The entry level Aspire One is nicely priced at $379 for the Linux Lite version.

Full specs:

Acer® Aspire one AOA110-1722: Available now for a MSRP of $379
Intel® Atom™ Processor N270 (1.60GHz, 533MHz FSB, 512KB L2 Cache)
512MB Memory
8GB SSD NAND Flash Module(3)
8.9-inch WSVGA Acer CrystalBrite™ 1024 x 600
Intel® Graphics Media Accelerator 950
Acer Crystal Eye Web Camera
10/100 Mbps LAN
802.11b/g Wi-Fi Certified WLAN
3-Cell battery
Multi-in-1 Media Card Reader
SD Storage Expansion Card Reader
Linpus™ Linux® Lite
3 USB 2.0 Ports

Acer® Aspire one AOA150-1570: Available now for a MSRP of $399
Intel® Atom Processor N270 (1.60GHz, 533MHz FSB, 512KB L2 Cache)
1GB Memory (512MB On-board)
120GB Internal Hard Drive(3)
8.9-inch WSVGA Acer CrystalBrite ™1024 x 600
Intel® Graphics Media Accelerator 950
Acer Crystal Eye Web Camera
10/100 Mbps LAN
802.11b/g Wi-Fi Certified WLAN
3-Cell Battery
Multi-in-1 Media Card Reader
SD Card Reader
Windows XP® Home
3 USB 2.0 Ports

Acer® Aspire one AOA110-1566: Available for a MSRP of $449
Intel® Atom™ Processor N270 (1.60GHz, 533MHz FSB, 512KB L2 Cache)
1GB Memory
8GB SSD NAND Flash Module(3)
8.9-inch WSVGA Acer CrystalBrite™ 1024 x 600
Intel® Graphics Media Accelerator 950
Acer Crystal Eye Web Camera
10/100 Mbps LAN
802.11b/g Wi-Fi Certified WLAN
6-Cell Battery
Multi-in-1 Media Card Reader
SD Card Reader
Linpus™ Linux® Lite
3 USB 2.0 Ports