I used the pen tool in Photoshop for both lineart and coloring. Took me about 3 hours.
You can also visit my Pixiv http://www.pixiv.net/member_illust.php?id=1440254
or Photobucket http://s1108.photobucket.com/albums/h408/Morrow_x/
for a more complete collection of my vectors ^^
I also have a tumblr: http://www.tumblr.com/blog/morrow-x
And a We Heart It: http://weheartit.com/morrow_x