Short answer (for the long answer do some research and read the Guides)
1. Jailbreak your Touch
2. Install the Community Sources
3. Using Installer, install Summerboard and one Summerboard theme
4. Put your new theme in the same location as the one you downloaded with Installer.
5. Make sure the theme's permissions are correct (match them to the one you installed).
6. Select the Vista theme with Summerboard
or
7. Wait until the Vista theme is on Installer.
PS. What's a "tuto"? Is it like a teabagging?
