This is a list of sites I’ve found I refer to constantly for both practical and inspirational reasons.  Hope you find them useful too.

Smith & Jamieson
Excellent quality Shetland Wool providers, good range of colours, particularly useful for vintage patterns calling for 2 and 3-ply yarns.

Ravelry
No need to preach to the converted, but if you haven’t come across this site, it’s an imperative for all knitaholics.  Wonderful project planning section plus groups and forums.

I Knit London
Great community website for knitters from the London-based shop.  Watch out for events, classes and knitting groups.

Retroknit’s ‘Knitting Vintage’ series
Fantastically useful guide to vintage knitting by the talented knitwear author, designer and vintage collector Kristen Rengren.  Includes sections on altering vintage patterns to fit, what size to fit and ease in vintage patterns, and a crash course in fashion history.  Print it, read it, refer to it again and again.

Knit On The Net
Run by Susan Crawford, knitwear designer, vintage fashion lover and author of ‘A Stitch In Time: Vintage Patterns 1920-1949′. Great free patterns as well as handy tips and knitting news. Also writes a blog under the pseudonym ‘Just Call Me Ruby’.

Ida Rose
Lovely site from the U.S. full of public domain 20th century reproductions - Fleisher’s, Bear Brand, Corticelli etc.  Well worth a look, especially for the 1930s books.  Will post internationally.

Dolly Dagger
How I love this site - ‘cool clothes for rock’n'roll chicks’ - rock’n'roll in the true sense of the word, cool vintage inspired dresses, skirts, tops and accessories.

Craft Magazine
One of the best craftzines around, now sadly defunct in the print form but alive and well in the digital world.  Get inspired by links to craft tutorials and projects.

Rod’s 1940s Events Calendar
Great site for those living the 1940s dream.  Really good links page for 1940s events, dance classes, vintage fashion etc.