In reply to Exile:
It's probably around 3 hours from Barcelona but less than 2 hours from Toulouse, but either could work.
The site martin09 was referring to is http://cafma.free.fr/plan.htm, which has a huge amount of info, mostly in French and is a really valuable resource. What it doesn't have are photo topos or any indication of which routes or crags are particularly good. The RockFax printed guidebook has plenty of things to go at and the app has even more.
As for other routes, there are good mountain routes at around the same grade in many of the other sites around Ax les Thermes, Ruhle and Bassiès, a lot of them fully equipped but many also needing trad gear. Further down the valley, around Tarascon-sur-Ariège there's more valley climbing than you can shake a stick at, as well as plenty of shorter multipitch routes. Most of the longer routes will face South, so if you're going at a time of year when the Dent d'Orlu will be climbable (roughly June to October) you'll either be wanting to stay high or to check out some of the many shorter, shadier crags in the valleys.
Presuming you'll have a hire car (pretty much essential for accessing the Dent d'Orlu) I'd say you can't go far wrong basing yourself anywhere close to the main valley between Ax and Tarascon.
Edit: And yes, the route is very good and impressively clean. If you don't find it too challenging, its sister route Durendalle (6b) is equally good and not a great deal harder.
Post edited at 09:30