Rosetta Stone offer pretty good interactive CD-Roms, not available in every language, but a good selection. Very expensive, though. There's a book/tape (or CD I think) series called, "Colloquial __________". We have Colloquial Lithuanian and Colloquial German, they're okay if you're going to be living somewhere, but a bit more than you need for just passing through, I think. Too pricey and bulky, and they focus on more day-to-day living type stuff - I think they're primarily geared to people who will be studying at in-country immersion courses. If you're planning to stay in, say, Slovakia, for a month or more, it might be worth while, otherwise I think it's a bit excessive.
To cut costs, when you get back within range of a lending library, it might be best to check out a couple of different language CDs there, to get an idea of what's available, and which are good. I used one to learn Italian pronunciation, and frankly, it was terrible. It was good for pronunciation, but the vocabulary was hopeless - had I relied it, all I could have ordered at a restaurant was a table, a chair, milk and a fork. In that order. Not exactly my ideal Italian meal. I can't remember the publisher of that one, but it's one that is widely available at BX/PXs in Europe. That's why I recommend checking them out of the library before you fork over $$$ for your own copy.
We picked up a Baltic Phrase Book - I believe it's a Lonely Planet publication, I can't find it at the moment but it has that look about it, which was reasonably helpful, and have a couple of Berlitz phrasebooks - one has about 8 or 10 languages in it, which is handy if you're covering a lot of countries. Mine doesn't have many eastern European languages, I don't know if they have a regional one. Those two we've road-tested, and have found them moderately useful. A lot of the phrases and situations don't really apply, but the transit stuff is quite helpful (it's good to memorize words like "train", "platform", and "please help", I've discovered!) I had a great time giggling over the "Dating" section with a couple of Polish girls I met on the train one night, we agreed that pick-up lines are just as corny, no matter what the language.
Somewhere along the way, we've picked up a Thai phrase book (never having been, I'm not sure where, how or why). It's part of the DK Eyewitness Guides series, and seems to be laid out as clearly as those guides typically are, and looks pretty good. Just from a quick glance, I like that it includes a small dictionary, in addition to the phrases related to specific topics, so you have access to a broader than usual vocabulary.
While we always make an effort to learn a bit of the language, we almost invariably found people who could speak English, except in really small villages in eastern Lithuania, so chances are if you start off in the local language someone will soon rescue their native tongue by speaking with you in English.