Visio 2010 isn't included in any of the Office SKUs as far as I know and must be purchased seperately. Also be aware that to build SharePoint workflows using Viso that can be imported into SharePoint Designer you will need Visio 2010 Premium edition.
Visio Standard and Visio Professional don't include the SharePoint workflow templates.
Paul Stork SharePoint Server
MVP Senior Solutions Architect: BlueChip Consulting Group
Twitter: Follow @pstork
Please remember to mark your question as "answered" if this solves your problem.
As Paul points out, like Project, though Visio is part of the Office family, the product is sold seperately.
You can create most drawings with Visio, but interacting with SharePoint has some restrictions. Using Visio Services requires Visio Professsional and use with SharePoint Designer, as Paul also pointed out, requires Visio Premium.
A list of what you get with the different flavours of Visio is found here:
Microsoft réalise une enquête en ligne pour comprendre votre opinion sur le site Web de Technet. Si vous choisissez de participer, l’enquête en ligne vous sera présentée lorsque vous quitterez le site Web de Technet.