Guys, thank you very much for your replies... I will be using realband and doing vocal experiments with pitch shifting.. Just in case you want to experiment, this is what I have in mind...

Basically record the main vocal.. Let's assume you have a chorus for which you want harmonies.. Make a copy of the lead vocal, and transpose the vocal copy down a third or a fourth and some tracks to sing with... Sing the harmony to the transposed vocal, which is easy now cause it's in your key... Sing another harmony track if needed...

Now, transpose the harmony tracks up and play it against the original vocal... With judicious mixing, you're going to get more realistic harmonies than using a harmony generator or trying to sing it out of your key and busting a gut.. I'll let you know how it works..