What was earlier known as Microsoft Office Outlook, now is just Microsoft Outlook. There are two versions of it available –
1> you can use it as a personal information manager,
2> it can also be use as an Office suite.
The latest download-able version, available now, as I type this post is Microsoft Outlook 2010.
Download free trial of Microsoft Outlook 2010
Alternative Software For Microsoft Outlook
1> Mozilla Seamonkey, is a free office suite.