text: There are a couple ways to send an IM from Yahoo IM.  The first is to click on the button with the talk bubble with the exclamation point in it.  Then you click on the other contact tab and enter the person's ID that you want to talk to.  The other way is to talk to them if they are already added onto your buddy list.  In that case, all you need to do is to right click on the person that you want to talk to and click send an instant message.  Hope that helps.