I have been remiss, and I apologize!  It should have occurred to me when I released Independence into the world that I ought to give some sort of status update on the second (and final) book in the series; I've had a number of queries (including one I haven't been able to respond to yet -- I am still trying, and will persevere, but my note hasn't been able to go through so far!), and so while I can't give as firm information as I'd like, here is the state of things.

I am still writing it.  The book does have a working title (The Line), and it is outlined, but I've drafted only a few chapters so far.  My most optimistic ETA is late summer of 2010, and I am going to aim for that.  Once I have a final version of the book, I'll be offering a free preview download here for a few days before the print version debuts (and if you've contacted me asking about the book:  I am keeping a list, and will email you when the free .pdf download is up!).
Independence is now available!  Er...if you're in the UK, that is.  The American side of things continues to struggle with poor supply lines, but England has gotten her act together promptly.  She remains a good sport, evidently!

So far, Stateside, the book remains available really only in its Kindle edition.  Once I figure out and fix what is behind the puzzling paperback delay, I'll update everyone!