wetravelcheap.com Run by experienced air mile users (reliable relatives of "Grandma"), it offers tips on how to get your air and hotel cheap.
I think we'll be signing up for the Rapid Rewards Visa offer. After checking Southwest Airline's website (just click on the bullet above the price to see miles instead of dollars), it looks like the 50,000 miles would be almost enough to get myself and 2 smallest children to our brother's wedding next year. (Yes, we're adding an eighth frugal sister).
The resort certificates mentioned also look interesting - $259 for a whole week (price per unit, not per person), and many of the resorts have units that will accomodate 6 or even 8 people. (That's a must for my family.) The offer ends October 15, so be sure to look into it now, if you're interested!