When using Vista to access a remote samba share on a linux/unix server, all is well until you attempt to access a password protected share. This is due to an incompatibility between the NTLM versions used in samba pre v.3.0.20. In order to work around having to upgrade your samba installation, which I'd highly recommend, you can always do the following:
1. Fire up the local security policy control panel applet, found under administrative tools.
2. Locate the Network Security: LAN Manager authentication level node under Local Policies/Security Options.
3. Change the setting to Send LM and NTLM responses.
Now you should be able to access your samba shares with impunity.