Website Backup and Download

I've found httrack (http://www.httrack.com/) very useful for this in the past.

If you use any tool to try download an entire site (not just httrack), make sure you show a little consideration to the site. See httrack's "what not to do" page for some pointers on that.

you can use wget to mirror the website [ provided it does not have flash or javascript based navigation ].

look here or just check command's manual. wget is available for unix systems and windows.

If you don't have admin access to the site to use the backup tool for the site then you could backup the HTML contents of your pages, from viewing the source the source, or if you just want the actual written content of articles, copy that. You can also download your images and other attachments from the site. This article gives you details of how you could do that in a more efficient way.

You can also use wget if you have it to get hold of the site information.

Bear in mind though that this will not give you the info you need to just take your blog and run it somewhere else, there is a whole PHP backend behind blogspot that is loading your sites etc.