Handle With Linux

Good installation howto for ubuntu linux on the lenovo thinkpad t400.

working out of box:
What works out of the box?

Wireless with iwlagn driver (Intel WiFi Link 5100/5300 WLAN controller)
G mode + WEP and WPA2 PSK (If you have the ThinkPad 11b/g Wireless LAN mini PCI Express Adapter III (Aetheros Chipset), see below!)
with status LED and everything!
Bluetooth
Even with Bluetooth Laser Mouse
Bluetooth can only be toggled together with WLAN on and off, to add a bluetooth-only-toggle (Fn+F6) that doesn't affect WLAN take a look here.
Intel Gigabit Ethernet Controller
Intel driver for Integrated Graphics (Intel Integrated Intel GMA 4500MHD)
3D acceleration out-of-the-box
VGA output

ATI fglrx driver for Discrete Graphics (ATI Mobility Radeon 3470 graphics)
To enjoy 3D acceleration, you have to install the proprietary fglrx Driver.
Touchpoint and Trackpad
Including scroll at the right side of the pad by default.
Optical drive
Including DVD burning
Sound card
built-in webcam with Skype
7-in-1 card reader from Ricoh (MMC, Memory Stick, Mem Stick Pro, SD, SDHC, XD, XD Type H Memory)
Only tested SD cards.
Control buttons/Hotkeys
Volume control buttons
Screen brightness control
Thinklight control
WLAN/BT/OFF toggle (Fn+F5 and mechanical toggle)
Media player control
Some ACPI features
Battery status, power graphs and history
Lid states and events
Suspend/Hibernate on a fully updated System!

What doesn't work at the moment?
Integrated Fingerprint Reader

Theres a new chipset build in, the "AuthenTec AES2810". So neither the thinkfinger nor the fprint Project support this Device at the moment.