honestly i think it would be really hard to do without heat styling.
What is your hair type naturally? If its wavy it would be easier but I think your best bet is using a curling iron.

__________________

all that glitters my new beauty blog*recently updated*

^^like she said, your hair will be easier to achieve this on if you have a wave to it. if you dont want to use a curling iron, you can try running a frizz cream and some sort of setting gel/mousse through your hair while its wet, possibly damp if it doesnt tend to frizz a lot. Then you can either put your hair in two french braids and let it air dry, or you can take small sections of your hair and twist each up, until all your head is done. Secure them with bobby pin or rubber bands but that wont leave an indention. let that air dry also. when your hair is dry, let it down spray it with a curl enhancing hairspray or one for texture and body, and gently seperate the plaits or twists with your fingers. NO BRUSH! You should have a similar look. Sometimes even after this, you might have to put a few big curls in with an iron, but at least you wont have to do your whole head. Try different products for different kinds of hold. Hope it works!!

This article might help you out a little bit: How to wave hair

two semi-loose braids on damp hair b4 bed would give that look easily, as long as ur natural hair isnt pin straight or fine

some kind of light frizz cream .... while your hair is damp... then put your hair in a few small buns ..let it air dry ..this works for me ..but 1 I don't have a lot of hair and 2 my hair is slightly wavy ..it's half wave/frizz and other half straight ..but give it a try. I tried this tip after reading about it in allure. good luck.

__________________

Hmm, there's this article about Joss Stones hair which kinda has a similar wave to it as in your pics, and they rec rag rollers
Long Hair Celebrity: Joss Stone
I'm not very familiar with them but there's a how-to anyway! lol hth!

__________________
Jessica
Representing the San Francisco Bay Area *the place I call home* 8)
...and yes, I say HELLA

I posted a thread on rag rollers, including that website. I posted how to make them and what to do with them.. enjoy
Rag Rollers

I've had great luck with Goody Sp'oodles for achieving that wavy look. They are these colourful spongey/gummy tubes that you'd roll into your hair.

After showering, towel dry your hair and work in your favourite curling product. Then dry your hair, but not completely -- you want your hair a little bit damp. Take the time to neatly roll them into your hair and leave them on over night (they are spongey, so they are much easier to sleep with than a set of plastic rollers in your hair). To my surprise, they stay in your hair fairly well.

These Sp'oodles really work! I think the trick though is to actually take all the time you need to roll your hair up with them neatly and tightly. And if you know your hair is curl-resistant, then I would roll them up in smaller sections.

__________________
"Hell is other people" - Jean Paul Sartre

where can you get sp'oodles?

You can check drugstores, CVS, Walgreens, Rite-Aid for Sp'oodles. Also Wal-mart/K-mart might have some..