MPEG Streamclip is a free video converter, player, editor for MPEG, QuickTime, transport streams, iPod. And now it is a DivX editor and encoding machine, and even a stream and YouTube downloader.
As a DVD ripper MPEG Streamclip is commonly used, and it "lets you visually set the In and Out points for the conversion so you can convert just the part of the file you are interested in, and also cut commercials and other unwanted parts, or edit the stream and join two streams with Cut/Copy/Paste."
A notch above in extraction features and some cost is Cinematize2 from Miraizon, which available for both Mac and Windows.
Note: MPEG Clipstream is not limited to exporting QuickTime; look under File>Export/Convert/Demux.
You can use the MPEG data on your DVD in Premiere without transcoding since Premiere can import .MPG files. Just copy the .VOB files from an unprotected DVD to a hard drive and rename them to .MPG, then import that into Premiere.
If you can't decode (ie, see) MPEG files then you have problems. Installing a codec pack like "K-Lite" should do the trick. Also Premiere Elements and other editors like Vegas and Liquid import from DVD, so you can download a tryout version and check it out.
On the Mac you'll need Final Cut or Apple's QuickTime MPEG-2 Playback Component for QT MPEG. I'm not sure what the free codec situation is now, beyond open source compressor/decompressors that come with ffmpegX and Visual Hub.