while not much information has been released about the two-hour season premiere here is something to tide the fans over and make up for the next few bone-less months, courtesy of SpoilerFix:
Episode 4.01: The He in the She (Season premiere?)
Airdate: August 26, 2008 (tentative date)
05/21 - Two hippies fish out a skeletonized wrist. Cam, Booth, Brennan and a grad student go to the scene to investigate. The lab is using some of Brennan's brighter grad students until they hire a permanent Forensic Anthropologist. In this episode, grad student Vincent Juarez is working along the team. Brennan doesn't seem happy with this tasking and sends Vincent back to the lab even if Cam brought him along. Vincent also has a hard time around Cam because he makes lame jokes and uses familiar terms that will not please Brennan. At first, the team believes the body is that of a female, 40-year-old Patricia Ludmuller. Further investigation proves that Patricia was born a male. Brennan and Booth still have therapy sessions with Sweets. Hodgins and Angela also appear. Source: SpoilerFix.com [Note: It is possible this episode airs later as rumor as it the series will start the season with the 2-hour episode they will shoot in the U.K.]
04/23 - "We're currently shooting our second episode back from the strike, and that's the first two of the eight we are shooting through the end of June. The last two of that eight will be a two-parter shot on location in London, England - we hope. The two that we'll shoot in England are supposed to air as the season four premiere on August 26, and then the middle four episodes of those eight will air after the season premiere, in September," [show runners Hart Hanson reveals.] Source: Kristin on E!Online
04/09 - Get used to the name "Vincent Juarez." I suspect we may be seeing a lot of him next season. He's one of Dr. Brennan's brighter grad students and he'll be joining the Squints until Brennan can find a new full-time forensic anthropologist. The yet-to-be-cast character loves to lighten the mood in the lab, but he definitely thinks he's funnier than he actually is. [...] In related news, does anyone know why Bones would be looking for a new full-time forensic anthropologist? Source: Ask Ausiello @ TV Guide [Note: This episode was labelled as episode 3.15 on the script.]
also, for any Bones/Booth fans, it has been confirmed that there will finally be some real lip-lock action between the two next season!