Sharp, many millers will saw lumber from customer logs. Depending upon the quantity, they can come to you or you can transport your logs to them. Their biggest concern will be if the trees are "yard trees", as these have a higher liklihood of having metal in them.
Millers typically fall into two categories - grade sawyers and yield sawyers. Most low cost millers saw for maximum yield, but for furniture grade lumber it is usually better to sacrifice some of the yield in order to improve the overall lumber grade and individual board quality (which a grade sawyer will do).
Expect to pay either by the hour or by the board foot (depends on the miller - most grade millers charge by the hour; and yield millers charge by the bd. ft), with you providing labor for off-bearing from the sawmill.
Additional charges will be incurred if the miller has to provide an off-bearer, if the miller has to sticker your lumber, and if any metal strikes occur. There may also be a mobilization charge if the miller comes to you.
There are two excellent millers that are not too far from you. Ivey Pridgen is located in Burgaw, and Jack Murdoch is located in Rolesville. Jack mills both portable as well as at his yard; Ivey only mills at his farm.
Both can be located in the sawyers link that Dan posted.
Chainsaw bar length is determined by the size of your powerhead, and the width of the logs that you want to mill. The bar needs to be at least 8" longer than the diameter of the tree. Many chainsaw millers use a 42" bar, and a powerhead such as a Stihl 084 or equivalent.