Where to buy:
The major Manufacturers:
http://www.volks.co.jp/en/
http://www.volksusa.com/
http://www.azone-int.jp/ (deputy needed)

Retailers
http://www.1999.co.jp/eng/
http://www.amiami.com/top/page/c/dolls.html
http://www.hlj.com/top/Dol

[some of the] smaller shops
http://parabox.jp/eng_new/
http://www.mimiwoo.com/
http://junkyspot.com/obindex.html
http://www.alicescollections.com
http://www.nine9style.net/index.php
http://dollmore.net
http://www.dollfieworld.com
http://www.leekeworld.com/En/default_leeke.asp
http://wigwing.com/ (Korean site, but has a separate English site just for ordering)
http://www.miruya.com/ (Can order manually from them by emailing)
http://ajumapama.com/

Auction Sites
http://www.ebay.com
http://tinyurl.com.dollfiedream (YJA Dollfie Dream section)
http://www.mandarake.co.jp/en/information/

random blogs and sites:
http://ameblo.jp/blog-dd/
http://ameblo.jp/oosm
http://blog.yam.com/hololo
http://blog.livedoor.jp/azure_toy_box/
http://holoblog.seesaa.net/
http://www.taitan-no.net/
http://kutsuneko.blog93.fc2.com/
http://azoneakiba.blog45.fc2.com/
http://7neko.web.fc2.com/top-custom.html
http://7neko2011.blog.fc2blog.net/
http://hanakobato.com/
http://momonotane.seesaa.net/ http://momo-man.net/
http://ameblo.jp/keita441/
http://sea.ap.teacup.com/doll/
http://whitemania.jp/dwarf_foto/
http://blog.livedoor.jp/teaoevo/
http://blog.ap.teacup.com/nersury/

Again, the above is just a small sample of resources, feel free to join active doll communities for up-to-date information:
Live chat on irc.rizon.net:
#dollfiedream
#doll
Forums:
http://www.dollfiedreams.com
http://www.denofangels.com
Flickr:
http://www.flickr.com/groups/dollfiedream/