As you know, your iTunes can't manage WMA format files and you need to convert them to MP3 format for them to work properly on iTunes for
iPad,
iPod touch(4),
iPhone(4) etc. Fortunately, this isn't too hard . If they are WMA (ie unprotected/unlicenced) then i think you can just drop them into itunes, and they will convert. (although the more i think about this, the more i'm thinking it's only the WinXP version of iTunes that can do this. if not, try ffmpegx (google it), which is a good cross-coder for many video/audio formats.
if it's WMA (protected, licenced, DRM), then you are willing to download a third DRM removal software to crack drm firstly, cause this DRM protection keep WMA from copying, playing, converting to other unauthorizable devices.
How to convert WMA to iPad, iPod touch(4), iPhone(4) etc.
I highly recommend a freeware third program allowing to remove DRM protection from WMA files fast and losslessly.
There are many paid
DRM removal tools which are promoted by spam, so don't be surprised if a program like that won't work as promised. Spammers never promote good software, they promote crappy tools that can't be sold otherwise.
See also:
Four ways to remove DRM from WMV and WMA (Windows Media video and audio files)