I am currently leveling using the recruit a friend program with my boyfriend, who is rolling a mage. Can someone pelase tell what the best leveling spec is for a priest if you are always in a group, never solo? As far as I can see spirit tap only works if I make the kill :( and it seems like I am mostly only smiting and healing at this point (only level 15 as of yet, soon to change).
What spec should I pick up for now and at what point should I respec to a different tree?
Yes, Spirit Tap only works if you get the last hit. If you're doing recruit a friend just go into Holy and Disc taking whatever DPS talents they offer. Looks about like this at 49. Use the Smite glyph and just drop a Holy Fire>Smite, then wand. At 50 switch to shadow like this. You'll want the Mind Flay glyph as well. The reason is that you'll do more good keeping Replenishment up with VT than you would being able to heal. It also gives your boyfriend a chance to not be stuck as Frost, since you can slow now as well.
If you just really like the gameplay of smite specs that's fine too. Outland leveling is stupidly fast and Northrend is even better about it. With Recruit a Friend you'll be 60 in no time.