Steam version of Borderlands just updated so the trainer will most probably not work now. Be patient. Hopefully new trainer will be here soon.
Do you want to do it the easy way or the hard way?
The list of tweaks that can manually be applied is here.
Obli over on the Gearbox forums made a nice little program that has most of the tweaks in it, but not all of them. Still a handy little program to have.
Well the configuration program has most of what anyone would want, there are however some tweaks that Obli hasn't incorporated into his program yet.
Obli is currently doing an overhaul on his program. You should still take a look at the list of tweaks, there might be some not in the program that you want.
Since this little update on Steam, there has been another update (bigger one this time) so any trainer will be delayed.
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem