One big step in the right direction is role modeling--i.e., the adults at home reading regularly in front of the children and discussing books with each other, etc.
Make reading a family activity, even if it's just you and the boys but a male role model will help a lot if one is willing (older brother, uncle, dad). Schedule one day a week for reading time together-ideally after a trip to the library.
Also make it your mission to find "THE" first book that each of your boys will fall head over heels in love with! (Like love there is THE one, the one you never forget! And from there you want to duplicate the experience again and again.) Remember too that each kiddo is different and you may have to try a few books before one grabs them.
My story: When I set out to find "THE" book for my reluctant reader son years ago (he was in 5th grade) I asked friends for recommendations of books that their sons had loved, I also asked the local librarian for titles that several 5th grade boys had taken out often. In the end it was A Wrinkle in Time by Madeline L'Engle by (not for your boys quite yet). I hooked him by reading it to him a few times during family reading time and before I knew it he was taking it to bed! My son, now 24, lists that book on his Mysapce page as among his favorites.
There's a relevant site called gettingboystoread.com.
My own take is that the single best thing you can do is to read to and with your children, sitting SIDE BY SIDE so you can explain/share details. Read the best, funniest, most famous stuff. Try not to give books meant for girls to your sons.
I suspect grades 2 and 3 are too soon to be worrying. What matters is that the boys are actually learning to read. That means this sequence: the alphabet, the sounds, sounding out, read anything. Understanding increases with practice and time.
I'm working on an article about helping boys to read and found this wonderful (dare I say it) macho site: booksforboys.com
The link below is to a grab-bag of information I've collected about reading.