A link for the Historical Novel Society
and their newsletter.
And in my opinion the best historical fiction written in the last 50 years is Patrick O'Brian's Aubrey/Maturin novels and Dorothy Dunnett's House of Niccolo novels - both of which unfortunately are not legally available in ebook. I think you can find them in audiobooks. Most of my other favorites have been mentioned already - Simon Scarrow, George MacDonald Fraser, Lindsay Davis, C. S. Forester, Steven Saylor, Rafael Sabatini, David Liss, Allan Mallinson, Bernard Cornwell.
edit: You might try "John Adams" by David McCullough", very good book. And if you like Forester's Hornblower books and since
you can't get the O'Brian ones in ebook, next best is Alexander Kent's Bolito's novels followed by Dudley Pope's Ramage novels...... a further note: Captain Frederick Marryat's "Mr. Midshipman Easy" books are available here at Mobileread. Some like him better than the others except O'Brian. Good reading. Also good is Allan Mallinson's "Hervey" novels but also not in ebook, I think.