I used the guide here >
http://samsunggalaxysforums.com/show...on-SD-card-fix
But I guess they are pretty much all the same.
First I flashed to JG5 (its one of the better firmwares)
Then rooted using the update.zip method
Then followed the tut on samsunggalaxysforums
Added the market fix which does work dont know where the apps DL to soz.
I am using a class2 16gb card and from what I have read when it comes to this fix there isnt much difference between all 3 classes.
The phone was a bit laggy after a few days out of the box, JG5 sorts out much of that & I was quite happy with just JG5 but I wanted faster lol so faster it is.
I didnt return the settings properly between doing ext3 & ext4 so I am going to re-flash & start from scratch but making sure I do the SD card fix before I install all my apps etc.