If you want to learn to draw Manga well, I'd say try pencil first, especially if you can get your hands on a sketchpad notebook and something like a 2H or 3H pencil (pretty light).
It might also be a good Idea to try and learn to draw from your favorite artist or a couple artists (in my case, it was Akira Toriyama and Rumiko Takahashi, with a little bit of Marvel and DC comics thrown in). This may sound like cheating, but remember, many Manga artists learn to draw/ink/etc. by being assistants or apprentices to other Manga artists (ever notice how the character designs of One Piece and Rave Master look eerily similar?).
The one thing to keep in mind is, don't COPY their style, just learn from it - try drawing some of the characters, but put your own spin on their designs. Artbooks help, especially medical journals as a reference for the human body, but the best way to learn is by simple observation; compare your characters to those of the artists and ask yourself, "what is it missing?" It's usually a little bit of detail here and there, like the ruffles in the clothes or how adding a few lines in the hair to show highlights can make it look better.
One way to start out is either making a curved cross for the face (at an angle - straight on is a simple cross), draw the frame of the head around that, and then follow up with the eyes first, then nose, mouth, and ears - the hairline is last; another is just to start with the eyes, then build the face and the body around those - the eyes give you an idea of how big the head will be and how it'll be proportioned, and the head gives you an idea of how big and how proportional the body will be (an average anime character is about 6.5 to 7.5 heads tall).
Like I said, learn by observation from those who already are in the business - those "How to Draw Anime" books rarely help, because each person draws differently, and has their own way of creating a character; what may work for the author of the book doesn't necessarily work for you. Have fun!
This is a pencil sketch of my character I use in D&D...
You know what they say: "when life gives you a T-Rex, go ninja-kick it in the head." - Rayne Summers, Least I Could Do
Proud to be a Jenova's Witness - WWSD (What Would Sephiroth Do?)
) And she just has some great pics. Like this one below is Ed and Al from Full Metal Alchemist when they are finally reunited.
This is just what she imagine it will look like. 
