Okay so the first question is whether or not you want your letters to be confidential. If you do, you must sign a document saying that you waive your right (under the family rights and protection act, I think) to look at the letters. Once that's done, you cannot handle the letters at any point. On the other hand, you can keep them non-confidential, but you must let your recommender know this. For obvious reasons, adcoms tend to trust confidential LORs more than non-confidential ones.
If you're going the confidential route (which I recommend), then look at interfolio.com or search this forum for how to outsource a letter service. My school has an office that does this for me, so I'm not a good resource for how to find someplace that you can use for confidential letter management.
In either case, all schools should detail on their secondaries how to deliver the LOR's. If they don't tell, probably the best idea would be to call and ask. Hope this helps.
