[snip]... i'd like to rename some of the filenames, is there any way to do this, whether thru the phone or by connecting it to my computer? Thanks
Depending on whether or not you are rooted depends on how many can be changed. If rooted, you can do both files saved on your sd card as well as in the /system/media/audio/ringtone folder.
If not rooted, you can only do the ones on your SD Card. Try to hook it to your computer using the USB cable and save them to the same path, only on your sd card: (/sdcard/media/audio/ringtones) and rename the files there. Or, download them to your computer, then enable USB storage and copy them to that location manually.
One side note, files downloaded from the web on your Droid usually go to /sdcard/downloads so check that location also to see if the files are there. Then use your computer or one of the file apps to move it to the other location.
HTH