Freeautobot is not as user friendly as I'd have liked, but once I fiddled with their code it was easy. You can paste it straight into your homepage as is, or edit it as I have and do with it practically whatever you want.
I got rid of the table (I don't like them, as you've probably noticed) and fitted the whole box into a div that I set up in the style sheet. Keep an eye on my website articles - there's a fair possibility that I will be doing some boxes in the style sheet very soon...
BTW, I've only had that opt-in box up there on my homepage since the beginning of April and I've managed to attract 45 opt-ins with my free eBook already! Ok, not exactly a crowd, but it didn't move much in the first month and a half. Most of the sign-ups have come in June, so it's growing steadily!
Which reminds me... I must set up an email campaign for when it hits 100!
