You got a sitar? Cool. I wish I could help you, a sitar is one of the items on my "got to get this someday" list.
Anyway, I've been to a bunch of sites that sell instructional videos.
One thing I know is that Eastern musical instruments work by using quarter steps, not half steps. I dont know if this is the case with a sitar, but if it is, dont try tuning it to your guitar or a piano or anything. It'll be tuned wrong then.