Create a file called '.Xresources' (note the . in the file name) in your home directory. Using your favourite editor, type into the file [code] XTerm*font: 9x15
Save the file and exit. In your home directory, find a file called '.bash_profile'. Open it and at the end of the file append
Code:
xrdb -merge ~/.Xresources
And you are all ready to go
HTH