You should live in the UK, much easier to watch Trek.
TNG - 6 episodes on every Saturday/Sunday Afternoon, 3 on each day. 2pm-5pm
Voyager - 2 episodes every weekday, early evening. 4pm-6pm
DS9 - As always, the best Trek show gets the worst slot (good thing there are such things as video tapes), 6am weekday mornings.
Enterprise - Series 2 is on Mondays 8pm.
TOS used to be at 6pm on E4, but the "any cult/sci-fi show" hating channel 4 took it off. This is the same network that is making sure Enterprise is unsuccessful on free to air TV by putting it on at 6pm on a Sunday Afternoon. I reckon that has to be the worst slot you can find, I think even the 11pm slot would draw more viewers.