In a recent article in LH Digest it was reported that the City of Oswego had taken over ownership of the lighthouse from the Coast Guard. Here is a related article. It doesn't sound like the light will be open to visitors any time soon.

http://oswegocountytoday.com/news/oswego-news/city-officials-receive-keys-to-lighthouse/

Here's another article about the transfer of ownership in an area paper back in May, there is a nice aerial image of the light and the harbor.

Oswego Lighthouse