Going and staying vegan can be rather daunting if you don't know any other vegans, if the vegetarians in your social group (assuming there are any) are already seen as scary militants (particularly if they don't like that position being challenged by someone doing more!), if you mostly know 'vegans' who cheat regularly using tenuous excuses, if you love your friends dearly but feel the absence of that particular common factor... you get the idea. It can be positively isolating if the people you hang out with are openly hostile and threatened by the prospect of eating anywhere that even has a vegan option - I hope that's the case for waaaay fewer people than it was in the past, but I hear enough stories that suggest the phenomenon hasn't died out quite yet. Anyway, more friends is always a good thing right? And I can say from experience that having more vegan friends makes it a whole lot easier to be vegan yourself. So here's some places to start looking!
There are vegan Meetup groups across the world, just type in your post/zip code to see where your nearest one is. I'd never used Meetup until my last big move, it's been a great way to get to know people.
If you don't quite feel like turning up to a cafe to meet a bunch of people you don't (yet) know - or don't have a local group - you can gear yourself up by getting to know other vegans online. My favourite places are Vegan Lounge and Vegan Forum.
The Vegan Society and ActiVeg both maintain databases of local groups and contacts. The Veggies Directory, meanwhile, is a treasure trove for all things vegan, animal rights, etc that you might want or need to look up.
And of course you can comment here, click through to other blogs, and maybe start your own... ;)