According to the website for last year, 30$ was the cost for pre reg. until the end of december. This should be close to the same time frames for 2010, and so I would say yes 30$.
http://www.kumoricon.org/?page_id=13Registration Prices and Options
Here are the registration options for Kumoricon 2009:
* Pre-register online, by mail, or at one of our promotional events. All pre-registrations cover the entire three days.
o $30 – until Dec. 31, 2008
o $35 – until Apr. 5, 2009
o $40 – until Aug. 16, 2009 (last day to pre-register; badges ordered after Aug. 2 will be held at will call)
* $45 – Register for the full three days at the door.
* Register for a single day at the door.
o $30 – Saturday only
o $30 – Sunday only
o $25 – Monday only
* $25 – Child registration (age 6 to 12) – Same cost whether pre-registered or at the door.
* Free – Children age 5 and under