Is there even such a thing?  Where to begin looking?  I'm not a home schooling parent but would like to help a friend. 

I know Auralog's Tell Me More, which we used for awhile to learn Spanish, has an ESL product.  Check with the Homeschool Buyer's Co-op (free to join) to see if/when they may have a group buy.  Or try one of the used HS curricula sites.

http://www.tellmemorestore.com/SearchResults.asp?Cat=65

http://www.homeschoolbuyersco-op.org/?source=18165

http://www.homeschoolclassifieds.com

That's all I can really think of, because I don't think there's much of a market for ESL in HS'ing.  Oh, also try CurrClick:

http://www.currclick.com

They have loads of early learning materials that would work well.

Thanks very much!  I'm looking mostly for "additional resources" to (highly) supplement our school's program at home, so any are a help.  :)