For our 2 week trip to Montenegro, I felt the need to buy a proper guide book for independent travel.
I finally decided for "The Rough Guide to Montenegro - 1st edition", as I have already made many good experiences with Rough Guides on several other trips.
As Podgorica is the capital of Montenegro, the Rough Guide has several pages about the city, including a detailed street map.
Rough Guides: http://www.roughguides.com/
I must admit that I am a huge fan of the "In Your Pocket" guides.
They are usually an excellent resource for information about travels to Eastern and Central European cities.
So I was more than happy that I could download the Podgorica guide from the In Your Pocket website; we didn't find the printed version during our stay in the city though.
The guide not only provides helpful basics, but also many off the beaten path tips and background information. Besides info about Podgorica, the guide also offers helpful tips about Lake Shkoder and Kotor.