this is easy just make a backup of the site as a zip file. download it then in windows 7 or xp extract all the files to a directory.
-in windows go to control panel / folder options
-click on search
then check the radio box "always search filenames and content"
it should look like this
now go to the folder you extracted the files to.
If its a website the malware links to simply type in the website url that your website is redirecting to in the upper right search field of windows (in windows xp the search field should be on the left hand side) your pc should now go trough all the files and find the one containing the code.
open the file in notepad and press ctrl+f again type or paste the website addy the site is linking to in the find field.
notepad should highlight the link in blue .
now simply remove the line of code or comment out using <!-- tag and --> tag.
if its a javascript injection finding the code could be difficult.
for javascript malware scanning use
http://sitecheck.sucuri.net/scanner/
it should give you the code causing the malware alert again aplly the above methods and search for the code,remove and save ..... hope this helps