There's a drop from the Basilisks around Terrokar that lets you raise your Scryer faction (and, I assume, lower your Aldor faction at the same time) so it's safe to say that there's a method for t'other side.
Edit: Here we are, directly thieved from WoWwiki, all credit to their site:
Switching to Scryer
To change your faction from Aldor to Scryer to access their crafting recipes (and undo all reputation progress you have made), find Arcanist Adyria, a Scryer in Lower City. She offers you a repeatable quest Neutral [62] Voren'thal's Visions, that requires you to find eight Dampscale Basilisk Eyes. Once you are Neutral with the Scryer you can no longer receive this quest. The quest gives you +250 Scryer rep and -275 Aldor rep (in bonus, the quest also gives you +125 rep with The Sha'tar).
If I remember right, she's around the north part of Lower city, talking to an Ethereal.
Edited, Apr 26th 2007 4:29pm by DandymanDan
Edited, Apr 26th 2007 4:31pm by DandymanDan