One piece of information though -for the love of God, avoid WD40. It's the worst thing to use.
I would avoid WD40 as a lubricant, as it's initials suggest it is a Water Dispersant, not a lubricant.
I use a Halfords pump squirt can, which has a very precise jet- though I've never heard of anyone else using it!
The key issue as has been said is not to use to much, and to clean off the gunk beforehand and excess oil afterwards. I use it on chain, jockey wheels, pivot points on derailleurs and pivot points on brake calipers.
For greasing bolts etc I use vaseline, and for bearings lithium grease.