Go to the “post new topic” link at the top portion of the message area (just to the left of the right column).
As for these bikes, I don’t think the years or mileage give either much advantage. If I was looking at these two, I’d get the one that fit the best. If both feel the same, I’d get the one that was the cleanest and/or had the most complete maintenance records. I’d probably also follow my intuition on the seller and how he represents his previous use and care of the bike. If it’s still a tie — go for the coolest color.