Okey-dokey! I've had the stage for long enough. Now it's your turn!
I plan on putting up a whole series of posts to introduce and talk about each of the Enneagram types one by one (since the Enneagram system is less well-known & understood than the Myers-Briggs system and it also happens to be my favorite now!!), so once I get those up, you will of course be welcome to read through them, if you like, as part of your figuring-out-your-type process. However, that's going to take me quite a while, so in the meantime, feel free to click on some or all of the links below and take my favorite Myers-Briggs and Enneagram tests to help you narrow down the possibilities of what your types may be!
For figuring out my Myers-Briggs type, ironically enough, the most helpful test for me was not a Myers-Briggs test at all... it was a Socionics one... and a very simple one at that, just one question for each of the four letters that make up the type name.
Before you Socionics fans jump down my throat, YES, I know that Myers-Briggs type and Socionics type are not always synonymous! Still, they're close enough, at least in my estimation, for this to work quite well as an indicator of Myers-Briggs type. For me, and for a friend of mine, the above Socionics test as well as another one from the same site were the only ones that were 100% accurate in typing us.
However, if you want one that's actually designed to be a Myers-Briggs test... my personal favorite is http://www.teamtechnology.co.uk/mmdi/personality-test/. This one is longer than the two Socionics ones. It typed me correctly, but not my friend, so I feel less confident assuring you of its accuracy -- but I found it to be fairly easy and pleasant to take, and the results pages indicate which other Myers-Briggs types are next-most like you, so even if it doesn't type you perfectly it may still be helpful and hopefully won't be too much of a waste of time.
After getting your results, go here to read about your type -- or any types you're comparing with each other to figure out which matches you best. (This page also includes descriptions of the Enneagram types; feel free to read through them as well if you wish to -- maybe they will be helpful to you, although they weren't that helpful for me.)
Another very nice page to check out is http://www.personalitypage.com/html/personal.html. It gives some valuable observations that apply to everyone, and then there are links at the bottom to more growth-related wisdom for each of the 16 Myers-Briggs types.
For figuring out Enneagram type, I have two favorite tests. The first is the one I already described in a previous post, the very quick, easy and simple Riso-Hudson QUEST (Quick Enneagram Sorting Test). For that I recommend getting the book that it appears in, if you can (The Wisdom of the Enneagram by Don Richard Riso and Russ Hudson); the book will be useful for many more things than just the QUEST, and both of my counselors highly recommended it as the best Enneagram book, so hopefully you won't be disappointed.
My other favorite Enneagram test is the upper of the two on this page. This one is much longer than the QUEST, but it gives you not only your main type but also your wing. Even while taking it I could already sense how well-made and accurate it was, but still, I was absolutely delighted and astounded to see that it nailed my type and wing perfectly, because it's the only online Ennegram test I've ever found that could do so. Later my mother took this one as well, and it did the same for her, so it's not just me!
The lower test on that same page also typed my mother and me correctly as far as Enneagram type and wing are concerned, but it MISTYPED both of us regarding instinctual variant. You choose whether you want to take it or not.
Of course, although these were the tests that I personally found to be the most accurate, you should still take the results you get with a grain of salt. There is no substitute -- ESPECIALLY with the Enneagram system! -- for reading up on each type and deciding which one sounds the most like you.
There are plenty of good websites where you can read about the different Enneagram types, but the one that finally convinced me of what my type was is www.9types.com/descr/.
Good luck; enjoy; and if you have any questions or make any exciting discoveries, let me know in the comments section! :)