2nd gear crunch, do a search and you'll find its quite common, if the symptoms are the same as yours.
If you know a bit about gearboxes, its the syncro that has worn and as Alpinehead said correctly you can hear it when cold more as the gearbox oil is cold. When the gearbox oil warms up, it helps.
To fix this you can try changing the gearbox oil to Redline MTL or if the problem is quite bad you may need a new box. Don't change between first and second gear too hard and it should be ok for some time
*brynmk2 beat me to it!*