Remember, if you have a Kindle or Nook (or whatever) you don’t have to wait until my books come out at third-party stores to buy them. You can get them directly from Siren-BookStrand on release day!
Kindle – Set up your Siren-BookStrand account with your Kindle email address, and make sure your Kindle is account is set up to receive emails. OR, use the USB cable, download the file (.prc/.mobi) to your computer, then drag and drop it to the Documents folder on your Kindle like you would as if it were an external hard drive.
Nook – Buy the .epub format, download the file to your computer, and drag and drop it via USB cable to your Nook’s Documents folder.
Kobo – I believe Kobo uses .epub as well, so ditto the Nook procedure.
Sony, et. all – You should be able to download your format (consult your reader’s documentation) and transfer it to your reader.
You can also use the Calibre e-book software to manage your book files: http://calibre-ebook.com/