Here are some of my favorites in Williamsburg/Greenpoint:

Restaurants:
DuMont (Union Ave. X Maujer St.)
Fanny (Graham Ave. X Withers St.)
The Queen's Hideaway (Franklin St. X Green St.)
Diner (Broadway X Berry St.)

Bars:
Pencil Factory (Greenpoint Ave. X Franklin St.)
Pete's Candy Store (Lorimer St. X Richardson St.)

Don't forget to breathe deeply and inhale that true Brooklyn smell... Have fun!

thank for the tips sqsq,
is it possible or advisable to bike from downtown to brooklyn??
being from amsterdam i am used to pretty much bike friendly traffic.

Also:

Williamsburg:

Larry Laurence [grand st]
Bembe
Savalas
Royal Oak
Union Pool [ch ch cheaaah]
Barcade
Turkey's Nest
Enids
Supreme Trading
Triple Crown


Places to Eat:

Planet Thai [great cheap sushi]
Snackies [grand st and bedford]
there's a Korean BBQ place next door too
Sea [if ya like B&T]
Chai
Scene Slice
Yolas [get a torta]
Dumont BURGER [S3rd & Bedford I think]
Relish
Enids
... and mad places in Greenpoint for brunch

if you mean downtown brooklyn, sure...if you mean midtown manhattan..maybe early morning. other places to check out in brooklyn:

cobble hill

gowanus yacht club (beer and food, cheap) smith st.
vinnies (italian-american food) smith st.
brooklyn social (bar) smith st.

park slope

prospect park (very good for biking)
5th ave (lots of bars and restuarants...most pretty good)

fort greene

fort greene park (small, quaint park...great view of manhattan)
five spot (cheap sould food and brews) myrtle ave.

greenpoint

lomzynianka (good cheap quirky polish food restaurant) manhattan ave.near nassau
peter pan donuts (go for the onepiece mint green dresses as much as the great donuts) manhattan ave.

brooklyn's big. too big for one trip. i'll stop now or i'll fill the thread.

wow. thats alot of tips! thanks guys!
i am in ny for 6 days, and as i have visited a couple times before i thought i would check out brooklyn. seems like i might allocate a couple of days to hang out there.

none of the traffic in ny is bike 'friendly', but there are too many of us for them to do anything. Both the williamsburg and manhattan bridge will take you to williamsburg and park slope respectively, and have seperate lanes for bicycles/pedestrians.

at the end of the night in williamsburg i would reccomend the alligator lounge for a free pizza when you buy a beer, so you may fuel up for the ride home.

dont miss DUMBO either

and of course, the famous Peter Luger's... great steak house, if you're into the whole meat thing.

Skip Alligator and do Capones - better music and close to Supreme Trading.

The only time I have been in NY I was taken to a bar in Brooklyn. It was a tiny place run by a old lady and they served beer in styrafoam cups.

Does anyone know what this place is called?

its the greenpoint tavern? wait, damn it. Is that right? It is on Bedford Ave right at the L subway stop. Not actually in greenpoint....... I think it also says Mary Ann's in the window? But yeah, that is the place of which you ask.

Brooklyn Social in Carol Gardens. Very good cocktails.

Soda in Prospect Heights is a nice bar, too.

Brooklyn Fish Camp, Al Di La, and Blue Ribbon Brooklyn on 5th Ave in Park Slope are all very good.

old lady + styrofoam cups = rosemary's greenpoint tavern. very cool if you dig domestic beers.

overall square and johnP did pretty well but I have to mention a few others:
(for all you graham L stop folk out there):

bars/etc.:
-the pour house (excellent neighborhood dive bar, jesse and lori rule)
-sweet-ups (can't believe no one mentioned this one yet)
-blanking on the name right now but it is a pub almost right next to rosemary's... it's pretty new and might not have the allure of more dingy places but the beer selection is excellent....
-grand central
-daddy's


food:
-Bamonte's - scores extra points since, depending on the night, it can be full of old mafia dudes on top of having good food.

Dr. No - Sweet ups and the coke lords HAHAHAHA. Never before have I seen so much powda ita hurt ya eyes.

and the pub is called Spike Hill...

But Larry Laurence KILLLLLLS ALL with deKonnick on tap!