It's definitely possible, but note that EC2 does not offer Windows 2008 yet - just Windows 2003.
EC2 itself has an inbound firewall which is controlled by the Security Groups you've set up for your account. EC2 instances might be running a software firewall, which can control both inbound and outbound traffic. The most common software firewall is iptables - if it's running then you'll likely need to configure it to allow both ports to pass through (one inbound, the other outbound).
In any case you'd need to set up your security group to allow access to the listen port, either from the entire internet (CIDR 0.0.0.0/0) or a sub-network range. You can do this from the AWS Management Console web interface.
Then, on the instance itself, you'd forward the traffic any where you want. Use whatever software you want to perform this forwarding.