Thanks for your reply, andyP

That´s exactly my point. After entering type and model number I´m stil offered both drivers. I tried their XP versions on a clean install of XP some time ago, and if I recall correctly, they seem to exclude each other (which is also to be expected) and both seem to work properly. That´s why I am confused a bit. Maybe it´s just a matter of taste which one to pick (the one has IBM in his name, the other - ThinkPad)
Regards
Marin
EDIT: Now I remember: after downloading the both wireless drivers I compared the file names of the packeges (before unpacking) and they were exactly the same. So I guess those are just two different names for the same thing. This would explain a lot except maybe for the reason why Lenovo had to put it twice on their site

Grüße, Marin
EDIT: Well, the benefit is that it can´t be overseen that easily when it´s put there twice... So maybe it´s a part of Lenovo service to assure that the customer will get his wireless working at any rate

IBM Lenovo Z61p | 15.4'' WUXGA | Intel Core 2 Duo T7400 2x 2.16GHz | 4 GB Kingston HyperX | Hitachi 7K500 500 GB + WD 1TB (USB) | ATI Mobility FireGL V5200 | ThinkPad Atheros a/b/g | Analog Devices AD1981HD | Win 7 x86 + ArchLinux 2009.08 x64 (number crunching)