There is no better way to learn software development than what you're doing. However, you have bitten off quite a large bite: awfully hard to go from zero to sockets protocols with GUI interfaces. I suggest you take it in steps: first make a program that displays something on the blackberry. Then make a program that connects to a web server, downloads a text file and displays the first few lines on the blackberry. And so on. Get there in steps rather than diving straight for the goal.
Actually I found a post from someone who was trying to do the same thing and the response to that post mentioned that, while there wasn't a J2ME client library for the GData Blogger API, what would probably be needed for one was pretty simple: an HTTP client, an XML parser and code for handling GData auth.
I found several HTTP clients (one that actually has a sample blog client) and XML parsers and there's sample code for interacting with ClientLogin, Google's installed application auth method. I've also gathered a bunch of articles and reference docs on the interfaces I think I'd need. I was going to open them up and see if I could put something together while reading what's necessary until I saw your post.
I'll back up and start with building something that displays "hello world" first.
Oddly enough, I haven't seen any detailed tutorials on that :-\