In cash play it can be a nasty leak, but in tournies it's viable to call from the SB with all sorts of hands with limpers in front. Harrington suggests calling from the SB if you get 7 to 1 odds
with pretty much anything.
The real art though is knowing when you havn't hit the flop hard enough and have to let it go as this can turn a justifiable limp preflop into a major leak. For example if you have J5 and there are 4 limpers in front and you call for 2% of your stack and the flop comes JT2 then it's knowing how to play it from there, and most importantly when to let it go that becomes the tricky part.
What you are really playing for is the Small Blind special, a juicy two pair or well-disguised straight that enables you to check-call and take down a big pot on the turn or river, but for every one of these you are going to find plenty of flops that you catch a piece of only to find that you are out of position and facing resistance and difficult decisions.
Definately worth speculating a few chips with the right odds though if you can avoid the bear traps