I am sure that there are as many different rates of pay as there are different magicians out there - but I was wondering how much a magic working in; 
Firstly it has a lot to do with age, experience level, novelty and things such as winning competitions, etc.
a restaurant Average rate is $20-35.00 per hour depending on the location and type of establishment.  The majority of first time gigs are typically tips and if you're lucky a free meal and sodas
at a wedding Depends on what you're doing; if you're strolling doing close-up we come back to what I said above.  The typical working pros I know get a $300.00 up front base + $100.00+ after the first hour + expenses when applicable (that can be a tricky issue, be careful)  If you're doing a platform show it depends on act content and if it's just you or an entire crew + livestock.  A traditional dove & manip act should (if it's any good) see no less than $800.00 for local (home town) gigs... if you have won awards and have a sense of name recognition (with the non-magic side of things) that can go as high as $2,500.00... more if you are doing more time and include some larger illusions
private party $300.00 to $500.00 should be on par.  Sadly, most magicians/variety performers settle for $75.00 to maybe $200.00 per gig (especially kiddie shows) which is outrageously low when you consider cost of living factors and how this is close to what we were getting paid back in the 1970s
corporate setting Again... experience, awards, age, what you do... when I was working tables at trade shows in the early 80s the average rate was $1,200.00 to $2,000.00 per 10-12 hour day + expenses.  If I brought in the Illusions (typically 8+ 20 minute bits per day) it could exceed $20,000.00 if the client wanted tailored pieces that supported their name, logo and products. 
If you are a close up magician - how long is your routine and how often do you get to repeat it?
  
Wisdom would have it that you are doing 5-10 minutes at each table and moving to the next.  You want 3 completely different routines + a few "extra" bits for special situations (birthday's, engagements, etc.) as well as something special to do with the staff if you work the same gigs week after week.  You will also want to "change up" the material about ever 8-12 weeks maybe sooner, due to repeat business and needing to deliver something fresh to such patrons.  It keeps them talking in a good way about you.
Do you charge an hourly rate - travel / mileage?
I think I've covered most of that... travel time, etc. would only apply when you have to travel a significant distance or, such as when working with big props, transport and logistic fees come into play.  I doubt you'll need to worry about such things just yet.  
 
 
Though semi-retired I work primarily in the area I live in and charge no extra rate for transportation for the most part unless I have to travel more than an hour's time in distance.  I do this for two reasons, the biggest being to detour folks from bringing me to locations outside my comfort zone... (long story) but the other reason is that my business focus is local... everything I've been working on centers on generating a new aspect of tourism to this region, not elsewhere... I no longer chase the dollar as it were.