This March 31, 2005 Google patent seems to indicate it might be true:
 Consider the example of a document with an inception date of yesterday that is referenced by 10 back links. This document may be scored higher by search engine 125 than a document with an inception date of 10 years ago that is referenced by 100 back links because the rate of link growth for the former is relatively higher than the latter. While a spiky rate of growth in the number of back links may be a factor used by search engine 125 to score documents, it may also signal an attempt to spam search engine 125. Accordingly, in this situation, search engine 125 may actually lower the score of a document(s) to reduce the effect of spamming.
Although "inception date" in this case is the date the content was posted, so unless you've got a time machine handy, you can't force 10 year old content to magically appear on your domain.
 Certain signals may be used to distinguish between illegitimate and legitimate domains. For example, domains can be renewed up to a period of 10 years. Valuable (legitimate) domains are often paid for several years in advance, while doorway (illegitimate) domains rarely are used for more than a year. Therefore, the date when a domain expires in the future can be used as a factor in predicting the legitimacy of a domain and, thus, the documents associated therewith.
This, on the other hand, seems pretty clear. Makes sense to me, anyway; if you're registering 10k domains to spam, you probably don't want to pay 5x as much to have them registered for 5 years. Particularly since you'll use them only briefly and move on in scammer/spammer style.
Matt Cutts touched on this in one of his webmaster videos too:
"How much weight does the number of years a domain is registered for have on your ranking?"
We have a lot of ideas and we file a lot of patents, but that doesn't mean we actually implement all those ideas.
He does not however say domain registration term doesn't matter, he just says "don't worry nearly as much [about this as you do about producing great content]".