This might be a better question for the Drafting Standards, GD&T & Tolerance Analysis forum.
Your Machinery's Handbook has enough information to make sense out of ISO tolerances. Your hole, Ø41H8(2X) translates to Ø41.039/41, and there are two features to be fabricated this way.
The H8 tolerance is recommended as part of a clearance fit, to be mated with an f7 toleranced shaft. Under ANSI B4.1-1967, this is classified as an RC4 fit. The H8 tolerance is called on some of the other ANSI fits.
Iso 2768 is a 2 part document giving tolerances for essentially machined & sheet metal parts. First part gives different tolerances for linear & angular dimensions based on size and tolerance class. Part 2 gives geometrical tolerances, again based on size and class.
'm' (Medium) relates to the class for part 1, 'k' relates to the class for part 2.
You will have to get a copy of the standard, you can find portions of part 1 free on the net, possibly under DIN 2768, but you'll have trouble finding the whole thing for free, and arguably shouldn't expect to.
It's a bit of a Dog from the standard US/UK practice point of view but the Germans use it so it must be good right?
ISO 13920 I believe does similar for welded parts but I'm not sure.
ISO 1101 is a geometric tolerances spec, perhaps comparable to part of what 14.5 covers in the US.
H8 is to do with 'standard' shaft/hole fits as drawoh says, ISO 286 should explain this, again portions are available on the net.