This is probably the easiest (and best quality) way to rip the audio from the u2 dvd to burn it to cd. It requires a dvd-rom drive, and lots of time ;-)
All of the software can be downloaded from http://www.vcdhelp.com/vcdtools.htm BTW, http://www.vcdhelp.com/ is a fantastic site for anyone that does any DVD->VCD, etc type of work.
You will need a dvd decoder/ripper (I use SmartRipper). Also get the DVD2AVI software. (a lot of other programs will probably work too, use what you like!)
Start up SmartRipper with disc1 in your dvd drive. You should see where you can select vts_01 or vts_02. By clicking the + on vts_01, you see title 1. Expand Title 1, and you see Angle 1 [01:47:49] Click on Angle 1, and you see 20 different chapters. Each chapter can be thought of as a track number for each song (with track 20 being end credits) At the bottom you can select what directory to save files in. You can choose to rip all the chapters at once, or rip them one at a time. Ripping all chapters at once will use a large amount of hard drive space (i'm guessing 6.5 gigs or so) I chose to rip each chapter separately, otherwise you'll have to cut the giant wave file yourself into tracks. By ripping 1 chapter at a time, it will make the track cuts the same as the chapters. I will refer to ripping 1 chapter at a time from now own. Treat it the same way for full disc :-)
After ripping the chapter load up DVD2AVI. File->Open the first VOB file (in the directory you placed the rip) Later chapters will automatically link it to other vobs if it is split. The screen should show a the first frame of the chapter you ripped.
Select Audio->Track 1. Under 'Audio 48Khz->44.1Khz' you have several choices of quality, higher quality sounds better, takes more time. Your call here. ****UPDATE***** select File->Save Project. select the name for the project it creates (you can delete it later,its just a reference to the vob) Anyway, when its done doing its thing, the directory where you saved the project file should have a wav file. I suggest listening to the first few until you know you have a good feel for doing this. Between tracks feel free to delete the vobs and the project file. Yay for cd quality wavs from the dvd!
Notes: I ripped 19+20 as 1 track (as some playing continues from 19->20) then I loaded it into my friendly wav editor and deleted the sound at the end (where the dvd displayed some logo).
I burned with Nero, and did 0 second pause between tracks, disc-at-once, I hate gaps between tracks :-)
When using SmartRipper, choosing different titles/chapters can let you rip the audio from the extras, as well as making mpg files of the extras, but look to www.vcdhelp.com for more on the mpg file makings.
Let me know of any problems