Here is a list of sites which you can advertise your blog give-away on and find out about other great give-aways that you can enter. I will be having a really big give-away soon. Everyone on my email list will be notified with an email. If you want to be notified just enter your email at the top left hand side of my blog.
Update: Go to this Audreys giveaways for a massive list of other places to advertise!
I also found a really helpful guide which will definitely be worth a read if you are to do a give-away it covers how to do one (what people should do to enter), how much you should give-away and other really helpful tips, you can read it over at this blog called problogger. I decided to start collecting a list of sites These are not only great if you want to do a give-away but also if you want to win some great gifts and art. A lot of etsy users do give-away's so you will be winning handmade beautiful unique items.