A service like www.rapidshare.com will let you upload files that are up to 200MB in size without paying or registering, so if you can ZIP or Stuff the RAWs into archives a little less than 200MB in size then you could upload these via the Rapidshare website and the primary photographer should be able to download them. A program like WinRAR will split up a large archive into whatever size chunks you want. The drawback to doing this, of course, is that there are likely to be 60-80 200MB ZIPs involved so it could be tedious for you to upload and her to download them, one by one.
Otherwise, along the same lines are her initial request, if it's an option, a dual-layer DVD burners are available and will store about 9 GB per disc. I recently picked up a USB external DL burner for less than $90. You would need to check with her if she can read DVDs, of course.
Or 16GB SDHC cards are pretty cheap, at least online, and you could put them all on one of those and mail it.
Thanks! My computer burns DVD's so this is the perfect solution. I wasnt thinking that DVD's can fit so much more than CD's
Regular (single-layer) DVDs are 4.3GB. Dual-Layer are twice as much, but even a 4.3GB SL-DVD is better than a 700MB CD.
Or you could send them on one of those new smaller external hard drives. They could go through the mail rather easily. After you have transferred the images and the drive is returned, you would have a handy extra drive when needed. I use one frequently transfer work from home to the office.