Giving out a health stone at the start of each grouping was as common for me as receiving buffs from the other players. It is one of the few utility group spells we get. However, I didn't find that the stones are used often/effectively. Potions are about as easy to come by at that level that do the same or much better healing. Still they can save lives. Not something you will hand out every 30 seconds though.
The soul stones you will definitely want to give out if anyone doesn't have one. They are IMO our best utility spell. Being able to res cuts down time dramatically. Especially pass em out to shaman/clerics.
If you are really looking to 'group friendly up' your warlock, then pick up herbalism and alchemy, or first aid. First aid very handy.
Edited, Fri Nov 19 14:10:29 2004 by Chaocle