Windows Azure is Microsoft's Cloud offering.  To get started, you can obtain a free trial subscription, or alternatively sign up for a free developer subscription at https://www.visualstudio.com/ which provides $25 usage credit per month for a year.  Both of these options require you to supply a credit card (prepaid or virtual cards won't be accepted).

To begin using your subscription and creating objects, you log into either the Classic (original) Windows Azure Portal or the new Azure Portal.

The most common objects you will create include Web Applications (websites), SQL Server Azure Databases (back end databases for your websites).  Alternatively you can create entire operating systems (Virtual Machines) if you want to configure Internet Information Server (IIS) and install SQL Server Express Edition (free edition of SQL Server).  With this option, to assist you with installation and configuration, and to automate the creation of free websites, you can use the Microsoft Microsoft Web Platform Installer .

Get a free trial:

You can sign up for the free developer program:

There is an older (Classic) portal, located at http://manage.azure.com which is being phased out in favour of the new portal, but can still be used for many features.  For example, here we see that you can create a Backup Vault to back up your virtual machines and restore them should there be a need to do so:

The new portal at http://portal.azure.com seems colorful and slick, but can seem a bit overwhelming at times with vast detail all on one page:

(Note:  Administrators you can edit here or manage your settings .  Other actions include manage themes, adding a page, or managing your menus.)