Question : SSO in ISA Server

Im currently in the process of evaluating Microsoft ISA server however my background is a developer and my knowledge of this is limited however one thing is that appealed me to this was its ability to doing singles sign on (SSO).
Looking at the documentation apparently you can set up something called a Web Listener, which will allow SSO between websites?
However this is as far as my knowledge goes so with this in mind&
"      Is this right first of all?
"      Does this work across multiple level 2 domains i.e. www.domain1.com and www.domain2.com
"      All my sites use forms authentication  but use different dbs, can ISA provide SSO out of the box for these sites i.e. so that Ill only have to log into one?
"      And Finally if the above is possible then can you please advice the best way to do this?

Answer : SSO in ISA Server

Not completely, no.

A web listener is an entity associated with a puiblished service that 'listens' on a particular port and IP address (or collection of IP addresses) for traffic and then forwards this traffic to an internal ip address/name. Part of the publishing rule allows for the association of authentication.

For example, standard web publishing allows for host headers to be used ie web1.domain.com and web2.domain.com and you can also support 2 different domains such as that in your example but these would normally be done with two rules and 2 ip addresses (you can only have one listener per port/ip address combination. ISA2006 supports SSO for web servers that are on the same dns domain, it does not support sso for multiple domains.

Here is a link that gives some guidance.
http://www.microsoft.com/technet/isa/2006/authentication.mspx

Keith