EDIT: From comments received, Archive Manager should in theory have WIM support. However for me trying to open a WIM gives a "Archive Type is not supported" error message. However, copying the WIM to my desktop and added a .7z extension allows Archive Manager to open the WIM directly. N.B. you need to install the 7Zip from the software center.
P7Zip has the ability to read WIM files. If you search for "7Zip" in software center, it will install the command line tool "7z"
use 7z --help for the options.
An example from my Windows 7 Recovery disc is as follows:
7z e /media/Recovery3/Patch/Modules/Acer-HQ1/SET/WinRE\ LP\ Setup/MOD01SET74EN0N0006.WIM 1.xml
7-Zip 9.04 beta Copyright (c) 1999-2009 Igor Pavlov 2009-05-30
p7zip Version 9.04 (locale=en_GB.UTF-8,Utf16=on,HugeFiles=on,4 CPUs)
Processing archive: /media/Recovery3/Patch/Modules/Acer-HQ1/SET/WinRE LP Setup/MOD01SET74EN0N0006.WIM[enter link description here]
Everything is Ok
the .exe from the download site (link above) installs OK under wine (I'm using wine 1.3) - so you can browse the wim using a GUI:
Googling around, a native linux GUI is in short supply - here is one I've found, but I haven't tested this one myself