Usagi [Usa] Momochi and her young companion, Mamezo, are sent by Usagi's grandfather to bear the child of the head of the Hattori clan for the sake of her own family. The head, Hanzo, denies her almost immediately and sends her home. Determined to stay, Usagi uses her bad ninja skills as an excuse to stay with him. Now she's being trained by him alongside other bride candidates for Hanzo.
Not as cliché as the summary sounds... There is great characterization and plot development. Though she comes off as your typical airheaded, clumsy, heroine she definitely has great potential.
(Be nice, I wrote this myself :P)
And Hanzo Hattori is HOT.
If you don't know what it is, then check it out! It's worth your time!
http://www.mangafox.com/page/manga/series/765/tsuki_no_shippo/ [<--It's completed here]
http://www.onemanga.com/Tail_of_the_Moon/
And if you like ninjas in general, join Lady Ninja's:
http://www.crunchyroll.com/group/Ninja_Headquarters
I recently discovered [i know, what kind of fan am i?] that there's a prequel to the Tail of the Moon Series called "Tsuki no Toiki." It mainly revolves around the other Hanzo and Princess Sara.
http://www.mangafox.com/page/manga/series/1643/tsuki_no_toiki/