In gvim, how can I set or change font size and type?

If you use vim, copy .vimrc to .gvimrc
1. cp .vimrc .gvimrc
2. open .gvimrc
3. add
 set fgn=Monospace\ Regular\ 12

After executing gvim, you can find changed font type and size.

http://www.troubleshooters.com/linux/vifont.htm