Yes, Alaska has diving. Its a good question. When I asked the question of people in California and the Pacific Northwest before moving up here 12 years ago, all I got was "no one dives in Alaska." Boy, were they ever wrong and I am glad I did not craigslist my equipment before moving. That being said, this is a big state. Since you mention Yukon, you can get to Skagway and down to Juneau where there is some very fine diving. Sorry, dont have the number of a dive shop down there, but if you a looking for a liveaboard, check out the Swell part of the Nautilus Explorer organization.
If you find yourself in Anchorage, check out Dive Alaska at 907-770-1778 a full service dive shop with weekend charters out of Seward into Resurrection Bay. Talk to Scott at the shop. i did a lot of diving with them this summer and it is a great operation. You can shore dive in Whittier (a short drive from Anchorage) but conditions there can be a little variable in the summer with low visibility due to plankton. Another option is to take the water taxi out of Seward, get dropped off and do do shore diving.
There are other options, but i am not familiar with them so I won't say anything. You will like Alaska diving.