I got this list from Mslexia, who ran an article on public advocacy last quarter. Whilst not specifically vegan, I thought these could be good opportunities for a vegan with something to say?
www.ethicalcareers.org - an online ethical careers guide
www.ncvo.org.uk - the national council for voluntary organisations (a UK one - sorry! - might still have some interesting links)
www.careersatgnl.co.uk - ‘The Guardian’ (UK Newspaper) runs the annual Hugo Young Internship Scheme, allowing participants to work for eight weeks on all areas of the paper while writing about social issues. If you’re not in the UK - just a thought - maybe other newspapers run similar schemes?