I love the idea Ardell DellaLoggia proposed in her comment #8 in this post on Rain City Guide: (Read the post then scroll through the comments till you get to #8)
http://www.raincityguide.com/2006/11/15/should-i-rent-or-should-i-buy/
Ardell's words: "I have counseled people who are zero down (have saved no money to date) and who are increasing their $800 a month rent payment to a $2,000 a month housing payment, to "walk the walk" by saving $1,200 a month for at least three and preferably six months before purchasing. Can't say they all listen to me though and usually they find another agent to work with who doesn't act like their mother 
That's OK. Different strokes for different folks. "
This blogger loved it and picked it up, too: http://www.johnsonteamrealestate.com/blog/index.php/2006/11/16/practice-making-the-payment/
What a good idea for first time buyers! Practice making that higher monthly payment every month for a few months by putting the difference away in a savings account. Yeah, yeah, we will know that income tax benefits will make some difference, but learning to save is never a bad thing, anyway.
Good point to bring to attention. With all the Zero down stuff that's going on, practicing to make the payment is not a bad idea!
Thanks,
kk