Syntax Help

I'm just trying to display a user's FIRST name and the FIRST INITIAL of the last name on my asp web page.
This works to displays their "firstName" and "lastName":


Code:
<%=oUsers("firstName")%>&nbsp;<%=oUsers("lastName")%>
But I get a variety of vbscript or asp syntax errors when I try to trim the "lastName" using something like


Code:
<%=oUsers("firstName")%>&nbsp;<%=oUsers(replace(left("lastName",1))%>
How do get this simple task done?

(If it makes any difference, the whole thing is inside html <td></td> tags as part of a table)