It is impossible to win... You can use math to figure it out. As long as you start he will win. No matter what you do it always ends with him winning.

No, it's not impossible to win. Let's say that the first row has 3 pealrs and second has 4 and third has 5. Try this:
Take 2 pearls from the first row. Then Devil will most likely take 1 pearl out of second row leaving there 3 pearls. Now take 3 pearls from third row leaving only 2 pearls. Now you are in a situation where you almost definitely win if you don't skrew up. The Devil most likely takes 1 pearl from second row leaving there 2 pearls. Take the last pearl from first row and now the Devin can only take 1 or 2 pearls from either row. What ever he does, just take pearls so that there's only one left.

Let me try to illustrate:
You Devil You Devil You Devil You win!
1. x > x > x > x > > >
2. xxxx > xx > xx > xx > xx > x > x
3. xxxxx > xxxxx > xxx > xx > xx > xx >

gah, dagobah destroyed my illustration :( anyway, it's possible to win if you know what to do.

Thanks be to you, hahuji, that I have won. :D

Heh, older than the internet
It's a fun game, though I've always preferred the third:
http://www.transience.com.au/pearl3.html

It keeps going when you win (and keeps score).
Also, it starts out with 2 rows, then adds a row once you win.
I'm pretty sure there was a second game too where you could play with 4 rows, but that seems pretty hard to me ^^