There are 2 very good courses available:
1. Polish in 4 weeks (level 1) (but it takes longer than 4 weeks to complete it). You also get a computer program to listen to the dialogs.
I too bought Polish in 4 Weeks and I think it's a very good course, particularly oriented towards self-study. However, as SzwedwPolsce said, unless you have an outstanding determination and willpower it'll take much more than a month to assimilate it!
The book tells two intertwining story in a soap-opera-like manner. The dialogues and situations seem to be practical and "realistic", that is not as contrived as textbook dialogues often are.
The audio recordings are of high quality; a funny thing is that, as the number of the voice actors is limited (about 6 I think) sometimes the same voice is given to different characters. Nothing wrong with that of course, only one woman of the series, Basia, has a very characteristic, cracked voice and it is funny to hear her turning up from time to time as estate agent, cashier, random pedestrian etc. :-)
I must also say that, at times, I was surprised by some twists of the story itself. Thinking about it, I found them slightly politically-incorrect for a textbook. This is not a criticisms, only I was left wondering if the book reflects a slightly different perception of some things or if it is just all due to the soap-opera quality of the story. Or maybe it's just me...
I'll give some examples (don't read if you don't want spoilers!).
The main characters at the beginning of the story are:
-Alice, about 25, American journalism student living in Warsaw. [she speaks perfect Polish, being American is a pretext to allow some kinds of questions]. She has got a boyfriend called Andrzej.
-Basia, about 25, Alice's best friend and co-tenant.
-Waldek, about 30, radio journalist and new acquaintance of Alice's who's trying to win her heart.
-John Brown, half-Scottish/half-Polish 40-year-old entrepreneur who grew up in the UK and has now gone back to live in Poland.
Here are some of the surprising bits:
-When Alice tell Basia of having met Waldek, Basia asks what kind of car had he got, because "ma dobry samochód, to znaczy że ma pieniądze!"
-Waldek begins a relentless (and ultimately successful) courtship on Alice: restaurants, theatre shows, trips to Kraków etc, all this behind Andrzej's back. Alice complains with Waldek that Andrzej works a lot and doesn't always have time to take her to discos. Big mistake! Waldek is all to happy to seize the opportunity...
-After a row Andrzej tries to make up with Alice with some surprise cinema tickets but Alice coldly dismisses him on the phone saying she can't go bacause she's going away with a "friend" (Waldek). Andrzej asks who it is but she just hangs the phone on him! This is the last we hear from Andrzej.
-That old fox of John Brown tries to hit on Basia at a local bar. Basia understands the situation immediately and is all to happy to be picked up by the (presumably) wealthy businessman. To justify the 15 year gap with Alice she says that after all "zrozumiałam, że najbardziej podobają mi się dojrzali mężczyźni"!
Comments? Personally I found the story line entertaining, better than the usual dull "The pen is on the table" texts for beginners.