The DVD's are actually DVD-recordable (4.7 GB of data). Picture and sound quality is good, thanks to the good source material which was a LaserDisc set of the movie. The movies are presented in letterboxed format, preserving the original aspect ratio of 1 : 2.35. The movies don't have subtitles, except for the parts when the conversation is not in English (e.g. between Gredo and Han Solo in the Cantina Bar). There is no chapter selection, but you can skip through the movie by pressing the next chapter button on the remote control.

I bought the movies at Ebay.com. All you have to do is search at Ebay using "Star Wars Trilogy DVD" as search string and you'll get a list of DVD's (and VCD's) on offer.

Buying the DVD's at Ebay saves me the trouble of capturing the original widescreen VHS tapes I own and burning the movies to SVCD's (I'm still waiting for the first dual-layer DVD-burner). I also own the Special Edition widescreen version on VHS and and the official Special Edition version on VideoCD and I propably will buy the official DVD's when they are released in september.
Buying the Original Trilogy on DVD is a bit of a grey area really. Officially it's not allowed, but as GL himself has stated once and again, these orginal versions do not exist anymore. So in fact he is not missing out on any sales to be made with them (also read a older column on this matter at The Digital Bits).