There's no problem with wands - for example, a Cleric with the Air domain can use a Wand of Gaseous Form just fine.
There is a problem with scrolls. That Cleric probably can't use most scrolls of Gaseous Form. It's Air 3, Brd 3, Sor/Wiz 3... which means most of the scrolls of Gaseous Form out there will be Arcane scrolls. The Air Cleric casts Gaseous Form as a Divine spell... so he can't use an Arcane scroll of Gaseous Form.
He can use a scroll of Gaseous Form scribed by another Air Cleric, because it would be a Divine scroll.
Where you get interesting results is on collaboration between two casters to produce a scroll. A Wizard always scribes Arcane scrolls... but the spell can be provided by another caster.
So a Wizard scribing a scroll of a Faerie Fire spell provided by a Druid yields an Arcane scroll of Faerie Fire... which can't be used by anyone except with the Use Magic Device skill, since Faerie Fire isn't on anyone's Arcane spell list.
A Wizard scribing a scroll of a Cure Light Wounds spell provided by a Druid yields an Arcane scroll of Cure Light Wounds... which can't be used by either the Wizard or the Druid involved in its creation, but which can be used by a Bard, since he has CLW on an Arcane spell list.
-Hyp.