There are many tour groups of Birthright (it's not one big group). The only frum group is Yeladim, of the OU Israel Free Spirit organizer. I just came off a male-only OU Free Israel last week, and it constituted of mostly yeshivish guys, even though it was NCSY. It's a great program, you see a lot of cool stuff, toivel yourself in the Arizal's mikveh, view Yerushalaim, tour the streets of Yerushalaim on Shabbos, and eat the Shabbos seuda by the kosel (at Aish), etc. Great offer you can't pass.