Evaluating the type of program you want to attend can be a daunting task. There are definite trade-offs and a lot to consider, including cost, time commitment, company support, and your future career path. In general terms, if you want to switch careers (function or industry), you may be best served with a two-year, full-time program, so that your summer internship can help you with that transition. If you want an MBA to enhance your career and you have the full support of your current employer, a part-time program may be a better fit. 
 
Start doing your homework early (no pun intended!) and learn more about the types of programs available. Visit the Assess Careers & the MBA and Find Your Program sections of mba.com for guidance.