A lot of the good Czech-English dictionaries are made for Czechs rather than English speakers, as there are many more Czechs wanting to learn English than there are English speakers wanting to learn Czech. It's much easier to find a textbook or phrasebook in the States than it is a dictionary.
I have several good Cesky-Anglicky Slovniky at home, but I got them all in the Czech Republic. Still, I'll check around for you, pun definitley not intended, and see what I can turn up for you, if you're interested. Are you learning Czech, or traveling there? Or both?