Belarus is still a very undiscovered country, therefore an up to date guide book is highly recommended for individual travels.
Unfortunately, the only guide book in English seems to be the Bradt travel guide - Belarus. In the past I was usually quite happy with Bradt guides for other countries, but I must admit that the Belarus guide couldn't keep up with the high expectations.
It doesn't list much helpful info regarding public transportation, but instead recommends tours with official tour operators. Also the descriptions of smaller cities is very limited. However, it is better to pack the Bradt guide than no guide book.
For German speaking travellers the Trescher - Weißrussland might be a good option. Also this guide doesn't list much practical info regarding transport, but at least the description of the sights are much more detailed and comprehensive.
Bradt Travel Guides: http://www.bradt-travelguides.com/
Trescher Verlag: http://www.trescherverlag.de/
Miscellaneous: Last time I was in Brest (May 2002) I saw several ATMs (near the banks), but no one of them had accepted my VISA Electron. They accepted (as far as I remeber) Cirrus/Maestro and (or) Eurocard/Mastercard cards (ask local people in forum for details). Fortunately, I could get the cash directly in the bank.
You may have trouble with ATMs and traveller's cheques in many places in Belarus. With the exception of Minsk.
You will still be able to find ATMs in Brest, but (they may be broken and you can hardly count on them being repaired promptly) if you wish to be more secure you will not find yourselves without any money in your pockets...
Take cash, preferably US Dollars in small notes.