Hi Chris,
Back when I had a 6" scope I started a thread on getting some help in finding planetary nebulas. It was a very informative thread with some great tips and information.
You'll just need to work out from the suggestions within the thread what is currently observable in our skies at the moment.
http://www.iceinspace.com.au/forum/s...anetary+nebula
The Ring nebula (M57) is indeed an awesome sight, as is the Ghost of Jupiter and the Blue Planetary (the last two are so colourful and bright).
Start with low (around 20mm) to medium power (around 15mm) with your eyepieces. You'll soon work out how much power you can throw on them. From what I've come to learn and understand so far, OIII filters generally work better with planetary nebs, but with the brighter ones, you don't have to have a filter to see them (I don't use mine that often to be honest).
Within this thread (on the first page I think), pay particular attention to the post by Jacqui (Blue Skies)- she gives a mighty fine tip on observing them.
In fact, I think this thread is so wonderfully helpful, it deserves a bump.
All the best with your chase on pn's - they are worth it!