I want to send some of my W:A Replays to a friend of mine, but he does not (yet) have W:A. Is there a viewing utility avaliable?

WA replays only contain input information. To make a viewer, someone would have to emulate the entirety of WA's engine precisely. Instead of doing that, everyone has just settled on using WA.

The best way to let your friend see something you've done in WA without him having WA is by making an avi of it by extracting all the frames (with the "Export Video" option), then using VirtualDubMod to compile those extracted frames (in .png format) into an avi file, and optionally encode it with a codec like H.264 or XviD.

Using that method will mean there is no sound, however.