Here's a quick breakdown of what there is:
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1950s-1970s original Astroboy manga (comic) - entire works translated and released by
Dark Horse in 21 volumes. At least two more volumes are due in the coming months. Available online through
Dark Horse,
Amazon,
The Right Stuf, and sometimes second hand on
Ebay. Searching for "Astro Boy" and "Astroboy" usually gives different results. Also have a look in any anime or comic book stores in your area. The huge bookstore
Kinokuniya also stock them.
1960s B&W anime (cartoons) - 193 episodes made, 104 translated into English, 36 available through
The Right Stuf on NTSC VHS.
1980s colour anime - 52 episodes made, 51 translated into English. All available from on PAL VHS in Australia from
Siren or in stores such as Myer/Grace Bros. Also available on NTSC VHS in the USA from
Manga Entertainment,
Amazon, and probably other places. There are also DVDs of the first 26 Japanese episodes with English subtitles (probably bootlegs) available through
Ebay or various online anime stores. The DVD picture quality is excellent, but the subtitles are very poor.
1987 colour comics - release by Now Comics. I think there were 20+ issues, but the drawing style is very westernised and I can't really recommend them except for their letters page from other fans. Hard to get, occassionally seen on
Ebay.
2003 colour anime - 50(?) episodes, all currently being translated into English. In fact they should have started showing them by now.
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So out of all that, what can I recommend? I'd say start with the 1980s colour series. The original manga and B&W series are more authentic, but unless you've grown up with them the medium can put you off a bit at first.
For all of the Astroboy stuff available, I recommend going through them in order.
The Dark Horse manga translation is all out of order - they've started with the more essential and interesting stories to get you in to it.
There's not much of the B&W series available, so if you're interested in that then it doesn't really matter what order, although it's probably best to buy volume 1 first as it shows Astro's creation.
For the 80s Astroboy series, the PAL and NTSC releases have the episodes in different orders. I recommend getting the first tape, which shows the birth of Astro and him starting school, then the tapes with Atlas on them and the tape with the two-part finale. You can get episode listings and tape listings off the Internet, or I can give you the specific info if you'd like.
The story of Astro's creation varies slightly with each version, and even the original manga has at least two versions within itself. Part of it was because Tezuka didn't start writing with the creation of Astro, he wrote that story retrospectively. Newer technology, artistic styles and mediums have also influenced the different versions throughout the decades. Ultimately, all the animated versions are based on stories from the original manga.
For the Astroboy soundtrack, try
CD Japan. Also, if you check the FTP Server forum thread, it will tell you how to connect to Anapan's Astroboy file collection and download some of the various themes in different languages.
And welcome, by the way!