<looks it up> Heh.... by RAW no. Page 37 DMG, "Do not award XP for creatures that enemies summon or otherwise add to their forces with magic powers." Planar binding is pretty clearly an otherwise 'magic powers' by RAW.
Aha, thnx.
You mentioned context, no we didn't want to grind summoned creatures.
That and I asked the question, cause Planar Binding is Calling spell and not summoning, meaning that the creatures actually die if killed.
-We are a level 8 group of 3 (Gestalt, Pathfinder, tho we still use the PHB, DMG, and MM for 90% of the stuff).
- We are in an Epic Demonic Red Dragons lair... no encounter with it so far.
- Bam, 5 Vrocks and 1 Hezrou appears, it takes em a while to reach our location, the place is huge.
-We manage to kill them, thanks to some awesome Bard maneuvers, and the Barbarian finding a Deas-ex-machina-cursed intelligent-bloodsucking-life-stealing-viscous-great-axe.
- I managed to nauseate 2 Vrocs and the Hezrou for 4 rounds, barb killed 2 Vrocs and died on the 3rd, the nauseated ones were moving away. Barb gets up via aforementioned axe, kills everything else.
At this point, I have just about no more spells, barb died once, and the druid (who expanded his wild-shape looong before we even got to the lair did some damage too, but nothing to write home about), had no useful spells.
The XP that this encounter would be worth (8400 per PC) would be enough get us to level 9 and half way to level 10. the DM assured us he will count the XP into the Boss fight, the Epic Demonic Dragon who bound it, or maybe some lackey.