I have been having an issue with wordpress just hanging on downloading, when trying to install an update through the internal auto update. After doing some research, I was able to find out that this feature requires php5 in order to function.
My web Host is 1and1.com, and inorder for your site to use php5 instead of php4 you must add a custom line in the .htaccess file in the root of your website. Simply add the below code to your .htaccess file, and you are good to go.
Today i upgraded my wordpress from 2.9.1 to 2.9.2 The upgrade process was pretty smooth. At first i had some trouble using the automatic update, so i ended up manually updating.
How to Manual Update:
The manual update process is quite simple. The wordpress website has full details on their website as to how to do this update. (http://codex.wordpress.org/Upgrading_WordPress) I will just go over the basics really fast.
Today while trying to update my blog to the new version, i received the following error: "Briefly unavailable for scheduled maintenance. Check back in a minute." any time I attempted to view the website. I was using the built in wordpress update functionality. After doing some research it appears that when an update is being performed wordpress places a file in the Root of the blog called “.maintenance”
This is actually a really simple fix. Just FTP into your web space and delete this file, and your blog should be back to normal, Provided the incomplete upgrade did not damage your blog in any way.
Why Does this happen?
During a wordpress update, WordPress creates this "dummy" file in the root, to block access to the website while the update is in progress. This is done so that if someone attempts to view your website while the upgrade is in progress, they may get ill desired results. If you are having problems using the auto update feature i suggest updating it manually, and researching why its not working. There can be many causes.
Hope this Helps!