ShiftSprinting

I play on a minecraft 1.6.4 server a lot (tekkit main) however the only way to sprint is by double tapping W.
This mod will simply allow you to start sprinting when you click shift (holding shift will keep you sprinting too)

You can also change the sprint key too, in the options GUI
It has FOV change too :)

How to install: 
like any mod... simply drop the file into your mods folder and it should work

Also, to compile the mod i used forge 1.6.4-9.11.1.953 and mcp-8.11 (aka MC versions 1.6.4). it tested it on the newer forge version (1.6.4-9.11.1.1123 i think)
and it worked. I haven't tested older MC version (e.g. 1.2.5) but it should work considering forge is quite backwards compatible, and how small the mod is

I did have another project, called "ShiftSprinter", but somehow i got locked out of it... even though it says i'm owner... but now this one exists. The other project doesn't have FOV change or a customisable sprint key