it depends what are you looking for.
start with old town, so you spend 1 day for that.
http://www.tourism.tallinn.ee/eng

there is some good clubs, if you like nightlife. for example on vabaduse you will find nice place called moskva, and 20 meter away another club Prive

one of the best pizza places is pizza americana http://www.americana.ee/index.php?page=184
but you have to think about not eating pizza, but trying out local food, you might find it very tasty.
places near raekoja called Olde Hansa
or Troika, just any in downtown where you will see nicelly dressed girls :)
good hotels are raddisson, viru, taanilinna, just pick any near downtown, so you will not have to take a taxi.

if you want to travel somewhere, you can go to parnu, or kuressare island.
don`t go to north-east, you will not find anything interesting there.
if you take a car, you can easily make a nice trip around, cause it is pretty small.
so just check out websites, you will find everything you need in there.

and here is some photos and cams
http://www.tallinn.info/flash/flash.html

Good hotels, don’t know if there’s any free rooms:
Wana Viru Hotel. I don’t remember the adress of the main entrance, but the “back entrance” is through the pub belonging to the hotel, and out on Viru Street (Main street in the Old town).
Tatari 53. 1 km from the Old Town along Pärnu mnt.
Pizza Americana have American, pan pizzas. Really good pizza by the way…
Then there’s also several Italian restaurants with pizza and pasta!
You’ll get food from most corners in the world there, I think…

This is a website, which I like very much myself.:

http://www.tourism.tallinn.ee/?setLang=3

Under “Enjoy the city” you’ll find “Dining and wining”. I think all restaurants are listed there! :)
Enjoy your vacation, Tallinn is wonderful! :D

And then also: I have too agree with “vestimo” about restaurants! Olde Hansa is fantastic…
But good luck, anyway! :)

Hmmm. Three days is a long time in Tallinn.

Hostel: Vana Tom. Mixed reviews, I know, but I found it okay and I am fussy. Location and general tidyness outweigh the crowded rooms and surly staff. I thought everyone was surly in Estonia (that is a generalisation, I did meet some nice people). But think Soviet era service!

Food: Great food to be had in the old square, on the patios. No worries there.

The only thing, you might find three days a long time in Tallinn, not tons to do.

Check out www.inyourpocket.com and look up Tallinn, its a great resource for this and some other eastern Euro cities!

Cheers! David

Visit the Old town of Tallinn, Pirita klooster (monastery), the Open Air Museum in Rocca al Mare, if you rent a car, you can visit places nearby, for example the waterfalls in Keila-Joa or in Jägala.