Yahoo groups offer many choices. Right now my favorites are Vintage Singers and We Fix It. You must be a member but signing up is easy.
I recommend Nicholas Rain Noe's Blog The Vintage Singer Sewing Machine Blog. He is very good at tutorials and an inspiration
Also check out My Sewing Machine Addiction blog. This is a great blog devoted to the restoration from inside out, of a 1940 Singer 201.
TOOLS. You really have to have the right tools. Get a set of hollow ground screwdriver bits. Again, The Vintage Singer Sewing Machine Blog has advice
stitchesintime@earthlink.net = Cindy Peters she has lots of parts and is very knowledgeable. Email her for questions. She's busy so give her time.
http://vssmb.blogspot.com/search/label/screwdriver
http://www.statewidesewing.com/
http://sewingstyle.com/
http://www.threadsmagazine.com/item/3751/machine-needle-know-how
http://www.tias.com/stores/relics/ A good resource for manuals for your machine
http://shop.sew-classic.com Excellent selection. Fast and reasonable shipping.
http://pages.suddenlink.net/joyof301s/glenn.htm For featherweight parts and info. One of the nicest guys around
http://pages.suddenlink.net/joyof301s/glenn.htm
http://www.whitesewingcenter.com/repairclass.php Ray White's Sewing Machine Repair classes. Highly recommended.
http://www.autonopedia.org/crafts_and_technology/Fabric_and_Dyes/Basic-Sewing-Machine-Repair.html#new_needle_bar Just found this one thanks to a post on WEFIXIT. Might be helpful
http://www.sewingmachineparts.net/ Guy Baker
http://www.mcmaster.com/#fiber-flat-washers/=hqlx4q Featherweight Fibre Washer
http://thefeatherweight221factory.com/page7.php
Needles
http://www.discountembroiderysupply.com/
http://needlebar.org/main/boye/index.html
Manuals
http://ouroldcottage.blogspot.com/2008/11/singer-319k-sewing-machine-manual.html
http://www.singerco.com/accessories/instruction-manuals
Facebook
There is a Vintage Sewing Machine group on FB. It is an open group and members hail from around the world. There is always something happening on that group
Some folks have a Facebook Page in addition to or rather than, a website. As I find them I add them here.
Rick Engel who is very smart and also a member of the FB group has a FB page. Cehck it out
https://www.facebook.com/pages/Sew-Mach-Tech/218982281467625