Take either trams 1, 2 or 5 from Amsterdam central station to Leidseplein. On the one side of the plein(square) you will see an area with trees and from March it is filled tables and chairs. Behind them are a number of small pubs, Dan Murphys is on the corner.

The address is
Leidseplein 24
Postcode 1017 PT Amsterdam
Tel nr is +31 (0)20 4223285

The red flag denotes where the bar is located. The first map is an overview of amsterdam, the last being more detailed.