OPT and Getting a J Visa

Hi,
I have an issue looking for some help.....I am trying to hire someone with an OPT VISA that will expire in January 2010. Unfortunately the person will not be an FTE and therefore not eligible for H1B sponsor. They are considering converting to J VISA.....questions 1) do they need to leave the country to do so?
2) how long does this process take?

The person can probably adjust his or her status from within the United States, although even assuming eligibility it would likely take several months to complete the process. You can get a sense of processing times here.