Hi, I would like to start a wordpress blog. I want to install and design it now on a temp domain and to buy the actual domain later on. How should i do that? If I install wordpress on a temporary address how do i prevent all the urls in the blog (for images and such) to be updated to the new domain? Hope you can help me, thanks.
Why don't you build your Wordpress blog locally, i.e. on your pc/Mac? If you download, install and configure xampp you can run a server environment on your local machine. It'll take some getting used to, but once you've got your head 'round xampp you can set up Wordpress blogs easily and have them running of your http://localhost address in your browser. When you're happy with your fully tested site you will need to migrate it to a live server so you'll have change some of the config settings for your WP install in order to get it work correctly from your new domain.
You can also choose free hosting with free .co.cc domain and learn everything. When you have learn ABC of wordpress then buy you domain and enjoy blogging.