Well, it depends on the pantheist.
Some adhere to what Dawkins calls "sexed up atheism." The material universe = God. No mysticism, no worship, no nothing. I don't really get the point of that, myself.
Others believe there's an underlying, unified consciousness. In this case, worship is more a celebration of the greater whole than anything else.
Then you have panentheists, like me. I believe the material cosmos is God's body. For me, worship is, like the second kind of pantheist, celebration. It's about expressing love and awe.