A physicist from Caltech recently tweeted that he'd been talking with the creators of Lost and talking with them regarding the time-travel.
Someone posted about it in the main Lostpedia forum, and I dunno how many people here read that (I don't personally, the people there are very... serious). There were complaints about spoilers, but there's nothing specific - just a very interesting inside look on the technical side of what's been going on but be warned that it does address some themes that might arise. The guy then signed in and commented on the thread... it's pretty cool.
And a blog he had written previous to season six regarding time-travel:
It's getting quite a bit of attention so I thought some of you guys might be interested in case you've missed or avoided it :)