Saiyuki Manga:
Created by Minekura Kazuya, Gensomaden Saiyuki was first published in 1997-98 by Enix Company, with appearances in G-Fantasy [similiar to Young King Ours] magazine. It ended with nine volumes when she changed publishers [Zero-Sum]. Now it's known as the ongoing Saiyuki RELOAD... volumes available.
Saiyuki Gaiden, the prologue to the series, takes place 500 years before Saiyuki. Gaiden is set in Tenkai [Heaven]. We get a peek at Goku as a child, and his relationships with previous incarnations of Sanzo [Konzen], Hakkai [Tenpou], Gojyo [Kenren]. We also get to see our Kanzeon Bosatsu [the 'Merciful Goddess'] on a regular basis. Saiyuki Gaiden is ongoing in installments.
Gensomaden Saiyuki manga is currently available in the US, licensed TokyoPop. Treats include the original wraparound covers from the 2002 Zero-Sum editions, cultural notes & such. I adore the textures. They've done an excellent job so far!
Saiyuki Anime:
The Saiyuki anime series was 50 episodes long [fun to watch!] and the new series, Saiyuki Reload, is currently airing in Japan.
There are also two movies, Requiem [Loved it!] and Saiyuki: Kibou No Zaika. Both films fit into the canon of the Saiyuki timeline.
Saiyuki [first series] is currently available in the US, licensed by ADV.
Check Baba Exits for where to purchase Saiyuki-licious stuff.
Saiyuki Soundtracks:
Where do I begin? Delicious soundtracks, including vocal albums. More later.