Worry Not, You'll Get Your Hulu Plus Service Without The Need For PlayStation Plus.

Turns out PlayStation Plus subscribers will get access to a unique preview evaluation period, but standard PSN users will be able to download and use the Hulu Plus service without an enhanced account when the functionality launches later this year.

The news was confirmed by Hulu themselves, who sent out an email noting:
[quote]
With the launch of Hulu Plus there have been many rumors started and we are trying our best to remedy the situation. Specifically to your question, the Playstation Plus service is only a requirement during the preview period.

Once the preview period ends you should be able to download the Hulu Plus app but that will still require the Hulu Plus subscription.

Right now we are limiting the number of users but Hulu Plus will be launching to the public very soon so stay tuned!</blockquote>

That's that then. There are plenty more details about Hulu Plus through here.