A pole of inaccessibility is typically the furthermost point away from a coastline. You can read more about them on the Pole of inaccessibility Wiki page. Whilst I have never visited the actual location of an official pole of inaccessibility and possibly never will, the closest I have come is about 500km from Point Nemo, the most remote point on the ocean.
This pole of inaccessibility is of a different nature, it is an abandoned concrete power pole. I have been driving past this for a number of years thinking that it would be tricky to climb. Recently I stopped and managed to climb the pole with only what was in my car at the time (including a new cache). There are however a number of options for the more prepared geocacher. From using a long ladder to showing up with a cherry picker, I expect that the majority of finders will opt for using ropes and harnesses or devising their own system of rungs to make the final approach to this cache.
Whatever method you use please think carefully about your own abilities and safety - the cache is not worth a serious injury. It is intended that the cache is left in position whilst signed. Make sure you can return yourself safely to the ground, getting stuck would be embarrassing. On the up side there is plenty of passing traffic to try and wave down if you do get in a pickle.