Free online grammar and writing handbook
Penny Gardner Italic handwriting videos for learning print and cursive letters (you can download PDFs of handwriting sheets and instructions for around £10 from here. It's a nice simple font, that's good for children who struggle with curves and flourishes in writing. Two of my children learned handwriting using this method, although personally I find italic quite tricky!)
British Council website - designed for adults learning English, but some useful grammar and vocabulary resources for older children who struggle with the basics. Click on tabs at top of home page.
Millstone Education - (dead link) free literature units for primary and secondary. Includes reading schedules, discussion questions, excerpts etc. US website, but uses classic books, so not US-specific.
Learner.org Introduction to World Literature course videos, text and geographical information to accompany various world literature texts.
FREE CLASSICAL CURRICULUM based on literature
Classical house of learning free reading list, literature guides, narration questions. Follows the 'Classical' 4 year history cycle (so could be used with Story of the World books) Useful for the reading list, if nothing else. May have a Christian slant, but you can pick and choose from the books selected.
CURRICULA TO BUY
Lots to choose from, so I won't list them all. We used the US Charlotte-Mason inspired Language Lessons Through Literature for several years, adapting it for our own needs.