Thanks for the response D. Brent.
I am giving away a chapter from my book and am going to use an opt-in form to receive it.
CANSPAM compliant... the whole nine yards.
I've never used feedburner.
I'll look into it.
I strongly recommend you using Aweber services.
Not only it's easy for you to insert opt-in forms on your blog (a matter of inserting a text widget), but you also have complete control like sending automatic e-mail after signing-up with the link to download, or even decide to send per 4 days (or any other day) some automatic e-mail (for example: lessons).
It's not a free service (19USD/month for up to 500 subscribers) but they are the best of breed IMHO (and recommended by top-bloggers). I am using them on my blog about discovering Madagascar- the island
Thanks to both you and D. Brent.
I will probably transition to AWeber in the future, for now I found and am using G-Lock Opt-in. It doesn't have the full functionality of Aweber but it does what I need it to do.