This can be dangerous, politically speaking.
Very, VERY often in small companies, a 'friend of a friend' did the IT work before they decided to hire a full time person. Put your feelers out about the previous IT guy FIRST. The last thing you want to do is sit down and explain to the owner how the previous IT guy was a retard, and then he says 'that retard is my brother in law'. Get a sense as to what they thought of him previously. If he/she was a well loved person around the office, and you come in guns-blazing bad mouthing them, your credibility will be shredded instantly.
And maybe it's not the past person's fault? Maybe management was stingy, and more or less told him to do things as cheaply as humanly possible? Many startups (and charities) are like this. Maybe that previous guy was actually doing a half-assed decent job, given the conditions. There's been times where I've looked at things and wondered why on earth it is the way it is, and then after a couple weeks/months, I realized the factors behind the decision. Maybe the past IT guy was a saint (at least in the eyes of the business).
Bottom line: Unless something is about to literally explode, get a sense of things first. Be careful, get a lay of the land, not only technologically, but POLITICALLY as well. It's usually not so simple as going in a bad-mouthing the previous decisions. Maybe the founder/owner/ceo is a bit technical himself, so you don't want to spend an hour poo-poo'ing his own work. Approach with tact.