I did WordPress 2.5 installation and saved screenshots with step-by-step instructions. In fact, there’s only two steps you have to take when you install WordPress. Here you go:
(at this point i assume you have downloaded WordPress 2.5, unzipped on your computer and uploaded its folder into your hosting FTP account)
Start with this:
Just open in your web browser the address of your blog directory ( i.e. www.mysite.com or www.mysite.com/blog/ ), and you will be automatically redirected to installation link and see a window like this:

Now do this:
1) Fill the required “Blog title” with the title (name) you want to give to your blog or site (for example “Joe’s blog”).
2) Next fill the required “Your e-mail” with an active e-mail, that is where you will receive your admin password, and this address will be used later to recover your password, in case you’ve lost it (and you will, trust me).
3) Next, tick the box to allow your blog (site) to report itself to Google and alike services - you want to become a famous blogger, don’t you? ;) Or, if you wish to write your suicidal emo notes and not let anybody know about it, choose not to tick this box.
4) Now you click “Install WordPress” and that’s it, in no time you get this screen with your user name (admin) and password that was randomly generated. Write it down, once logged in, you will be able to change it to a more safer one, like “qwerty” or “admin12″ 8)

There you go, just copy your brand new password and click on “Log in” thingee. Voila, you’re now a l33t blogger with your own blog platform! ;)
Leave a comment if this worked for you or you have some trouble!
Thanks for watching,
Helmut.