The Making Game of Thrones site has a new article, by way of Bryan Cogman, which is essentially the official pronunciation guide for the first season.
One of the more interesting aspects is the choices, as presumably these are mentioned in the series. So, for example, it looks like we can look forward to Harrenhal being explicitly mentioned. So, too, is Essos, the as-yet unpublished name for the Eastern Continent. Neat. I recall when I was at the production offices that it was noted that there were some minor issues in the 20 minute reel George and Parris saw with actors mispronuncing Arya’s name and the title Maester, which Bryan acknowledged and said they’d fix these things in ADR.
On the whole, the pronunciations jive with what we’ve heard from George, although there are some minor differences—he noted ser is pronounced the same as sir in the past, so “SAIR” seems to be a very minor change. Some of George’s own pronunciation notes can be found here. And for those still wondering, it’s JAY-me, not JAIM or HI-me. ;)