Hi!!! soooo glad you're interested in digital scrapbooking ! it's soooo much fun!
the printing of digital pages had me stumped too. the easiest way to print a 12x12 page at home is to just print them out at an 8x8 size on 8.5x11 photo paper and just trim the edges.
however, if you use 8.5x11 size to do your digital layouts (which is the size i do all of my layouts on and i LOVE it!!) you could also, of course print them at home. however i will say that which ever size you choose, probably the BEST way i have found to have them printed is to go through shutterfly.com. the do INCREDIBLE work! they print all of your pages (full bleed... which means there are no white margins... they print all the way to the edge of the paper... it's gorgeous!) then they bind them all and put them in a "coffee table" type book with a really nice cover. i've had one made and it just turned out beautifully. they can get a little pricy, but printing them at home can be JUST as expensive... those pages can suck the ink right out of your printer in no time flat! anyway... i've tried it all and i DEFINITELY reccomend shutterfly. there are a couple of places i've heard about that can print just your pages, but i've never done it that way only because i never seem to like how they look just sort of "loosly" in an album. i'm sure there is a better way to do that and make it look nice, but i haven't found it. anyway... quick note though... if you decide to use the 8.5x11 size to scrap with and want to do a shutterfly book, be sure to do all of your layouts in landscape form... that's the only way shutterfly can currently print using that size. but they do all different sizes, including 12x12... you should check out their website.
anyway... if you have any more questions... let me know. i'd be HAPPY to help you get started!!!