Quitting my job?

I am planning on leaving my current job, and am in the middle of searching fo rnew one, i have ben there two years and have had 3 bosses in those two years-the place in which i work was never run well and i never felt appreciated with the last two bosses and that's one reason i am planning on leaving, the other being financial reasons...anyways my new boss is great, she's getting things on track and she is very attentive..the other day she asked if i was happy in my job--and of course i said yes because i don't want any bad feelings and gossip going around-because i might not leave for a bit but now i feel guilty because there may be prespective employer knocking on my door--what is a good way to quit without making it seem like i am #1 a liar and #2 i don't want her to take it personal...any suggestions plus i know of someone would be great at the job and wants it...help me in wording my resignation? thanks