Buy airfare well in advance or last minute?

Hi Laura,
Here's some great advice from a previous post:

Purchasing Airline Tickets

We bought in either Jan or Feb for travel in June. Start checking the prices in the early part of the year.

I just always have a set price of what I want to pay and when I see it and feel that its a good deal, I take it. Im glad because I bought my Denver to Heathrow ticket last month for my November trip to London, and I paid about $640 for round trip, non stop on British Airways, directly through British Airways and not Expedia, etc (Expedia was actually about $27 more and also charge consolidator fees!).
Now the same tickets are almost $800. Maybe it will go down again but since I felt that I was ok with what I paid, then so be it! With gas going up yet again I dont think anything is going to be much cheaper later in the year.

Advice from the above respondents is good. But don't disregard the incredible deals that are available right now. Many of the fares rival what I paid in 1979 for my first Europe trip (in actual, unadjusted-for-inflation dollars). If any of these deals work with your itinerary, grab it.

You can track the ups and downs of prices using www.kayak.com

Usually between 6 and 3 mos out, you see the best rates, and the most seats on the market. If you see a price you like, go for it. Statistics say, there's an 87% chance it will increase.

So true Chris!! My flight I paid $641 for a month ago is already about $800 now. I know I shouldnt check but I do because I wanted to make sure I got a good deal!