I am trying to transfer mp3's and wav files to an 8800 to use as ringtones...what is the best way to fo this? Desktop Manager? I work off of a BES

to use Switch Device Wizard in Desktop Manager to move everything from one BB to another.
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Good luck, AND welcome to the forums.

trying to get some files off of my PC to use as custom ringtones.

Do you have an SD card? If so, enable Mass Storage on the 8830 and just move them as you would to any USB drive.

If not, upload them to a storage website, like a yahoo briefcase, or google folder, and from your BB, browse to that site and download.

You can also use the media manager in the latest version of Desktop manager. Simply browse to the file, using the media manager and drag it over to your BB. Pretty simple.

Yes the media manager is the best bet for transferring ringtones that are located on the device and not on an external storage card. Personally I have found that there is no detrimental effect of having the ringtone stored on the SD card VS the actual device but I would be curious to see if anybody has tested this out fully.

Having them located on the SD card has not affected me. And it keeps my device memory clear.

I have used Media Manager a few times. Real bulky and slow. I have found simply moving the files via USB is quick as a flip.

Its a shame it doesn't seem possible to save .wav file attachments from emails. This would be the easiest way. I attempted using the media manager from the latest desktop manager and it just did not work.

Well, it was described above other options to do what you need. You didn't answer my question, so it difficult to determine why your Media Manager won't work.