Oud and Makam Music Theory Websites
Mike's Oud Forum: An awesome and very active forum with a ton of information on the oud, where you can ask any questions you might have.
Oud Cafe: Mavrothi Kontanis' site on oud basics, makams, and exercises.
Oud Eclipse: David Parfitt's very detailed site on the history of the oud, basics, theory, artist, makers, and more.
Oud for Guitarists: Navid Goldrick's site, with lots of great videos, a blog, and a couple of online courses, with a focus on Arabic and Persian styles.
Arabic Maqam World: An excellent site with detailed analysis of Arabic maqams, ajnas, modulation, and more.
Turkish and Arabic Sheet Music
Neyzen.com: A very large source of Turkish sheet music in 91 different makams, sufi music, folk songs, and more.
Books
Turkish Music Makam Guide, by Murat Aydemir: An outstanding book that details 60 Turkish makams and includes 2 CDs with a taksim/improvisation and part of a well known composition in each makam. Unfortunately this book is difficult to find outside of Turkey.
Makam: Modal Practice in Turkish Art Music, by Karl Signell: A great book that covers Turkish art music and makams in detail.
The Maqam Book: A Doorway to Arab Scales and Modes, by David Muallem: An excellent book on Arabic music theory and Arabic maqams.
School of Oud, by Mavrothi Kontanis: A short book covering the fundamentals of oud playing, exercises, compositions, and an analysis of three makams.
The Basics of Oud, by Marina Toshich: Another good book on the fundamentals of oud playing with a great selection of well known Turkish and Arabic compositions.
Music of the Ottoman Court, by Walkter Feldman: An oustanding book on Ottoman Court music including musicians and instruments, makams, and an analysis of pesrevs and semais.
Demetrius Cantemir, The Collection of Notations Volume 1, by Owen Wright: Very difficult to find and very expensive, but a treasure. This book includes more than 300 compositions of classical Ottoman music collected and written by Demetrius Cantemir in the late 1600's/early 1700's.
Demetrius Cantemir, The Collection of Notations Volume 2, Commentary, by Owen Wright: Much eaiser to find, less expensive, and as valuable as volume 1. This book has over 600 pages of very detailed analysis of the pieces in the Cantemir collection.
Oud Strings & Accessories
OudStrings.com: If you live in or around the US and need oud strings or accessories, this is the place to get them. The site is owned by Brian Prunka, a great oud player and a very nice and helpful guy.
Music-Strings.de: If you live in or around Europe, this is the place to buy your strings and accessories. The site is owned by Matthias Wagner, another great and very helpful man if you have any questions.
Oud Makers
Faruk Türünz: One of the most well known and highly regarded luthiers in the world, located in Istanbul. I bought my ouds from Faruk, and can highly recommend them.
Mustafa Copcuoglu: A very highly regarded luthier in Istanbul. Necati Celik and his students get their ouds from him.
Bulent Eryalman: A highly regarded luthier from Izmir, Turkey, with ouds priced lower than well known Istanbul luthiers.
Yildirim Palabiyik: Another luthier from Izmir, Turkey, who makes very nice ouds at very reasonable prices.
Tasos Theodorakis: A Greek luthier in Thessaloniki, making very high quality Greek/Turkish style ouds.
Nazih Ghadban: Terrific Arabic ouds that look as beautiful as they sound, made in Ras Baalbek, Lebanon.