WebSphere is the application server. As an application server, it has an open port on which it listens to http requests. Clients can invoke resources through this port directly, but it's not a good architecture.
Instead, you have a web server sit in front of the application server. This listens on port 80, and forwards requests for
Servlet ans JSPs through to the websphere applications server. The web server can be pretty much any of the major web server vendors, although apache is free, and the IBM Http Server (IHS), which is based on apache, is typically recommended by IBM.
Is that what you're getting at? Check out my WebSphere website
www.pulpjava.com for some free tutorials and discussions on typical websphere architecture, and the web server plugin that WebSphere installs in client facing web servers.
Kind regards,
-Cameron McKenzie