I was wondering if there is a way (without clicking on each thread separately) to mark all of the threads in a topic as being read? Thanks for your help

Go to the individual thread box you will find a Mark Topics as Read option. click it and all the messages in there will turn to read mark.

example.

viewforum.php?f=7

If you are using the default skin, there is a "Mark forums read" near the bottom right of the board index.
There is also a "Mark topics read" button at the top right of each sub-forum.

thanks that worked great

Just for those who use the new skin: the "mark topics as read" link is in the top right corner above the topics, under the page navigation.