At this time, Vesta doesn't directly support Windows clients. However, it's easy to give them access to the repository by re-exporting it using Samba.
All you need is a Vesta client machine with Samba installed. Simply add this to the end of your smb.conf configuration file (probably /etc/smb.conf or /etc/samba/smb.conf):
[vesta] comment = Vesta Repository browsable = yes writable = no path = /vesta [vestawork] comment = vesta-work Directory browsable = yes writable = yes path = /vesta-work/%u
After adding this (and restarting the Samba daemon to make the changes take effect), you can access \\sambaserver\vesta and \\sambaserver\vestawork from a Windows machine. You can map them to drive letters V: and W: to make them easier to access.
Of course this won't allow any of the client programs to work on Windows. You'll still need a shell on a supported platform to create packages, check out, check in, etc. However, this will allow you to use native Windows editors and filesystem utilities. You can read all files in the appendable part of the repository and make changes to your checkout working directories. The user you log in as will determine which subdirectory of /vesta-work appears in \\sambaserver\vestawork. Changes that you make with Vesta command-line tools (e.g. creating packages, checkouts, etc.) will show up in the drives exported by Samba.
[We're no Samba experts. Suggestions for improvement are welcome.]