Update 9/5/12: This freebie is still available! If you have a LEGO nut like I do then I'm sure they'd enjoy this free magazine subscription.
If you sign up for the free LEGO Club, they'll give you a free subscription to Lego magazine for two years. No strings attached. This is a such great magazine for kids!
You can get the subscription for the free LEGO magazine by selecting your country and age range of the child who the magazine is for. You'll then receive an email that will let you finish registration. You'll receive your first magazine in 4-6 weeks.
This freebie is for residents of the U.S., Canada, U.K., and Ireland.
Don't forget about the free LEGO builds for kids that happen monthly.