It is not stated anywhere in the armybook that they cannot. In the description of the razordons however, the rules clearly say "if they march, they cannot shoot". Why should razors have such a rule and sallies not, if sallies weren't allowed to march and shoot?
As Asrodig noted the rules clearly indicate that Salmanders can move and fire. Although I will agree that it is odd that it is called out explicitly in the Razordon entry that Razordons cannot march and shoot; while similar wording is absent from the Salamander entry. But, we must consider GW's track record on consistent writing even within the same book. For what it is worth I know the question is on the lengthy list of Lizardmen questions at the Warhammer Forum: http://warhammer.org.uk/phpBB/viewtopic.php?f=3&t=54268. Personally I think it is folly to assume that spout flames is a breath weapon despite the similarities, as the rules do not refer to it as a breath weapon. However, as always I would love to be wrong as that would only benefit me.
I suspect the caveat was mentioned on the razerdon entry because it had just finished saying all of these things that didn't effect the BS for the razor shots...so it made sense to make sure to add that restriction there so people didn't jump to the conclusion that since all of those things didn't effect their ability to shoot that they could march as well
People don't generally agree on this one. you just have to agree with either variant before a game. maybe roll a dice. until there is a faq thare can not really be a definite answer to this question (as well as many others about our new book....)