Building a road bike beginning with only its frame is easier said than done if you're a novice. On Ebay, you can find numerous frames or framesets (frames that include the fork) at bargain basement prices. If you are not sure how to build a bike or whether you want to or not or if it will save you money, then you are at the right place right now.
So will it be worthwhile and cost effective to take advantage of the great deals you can get by buying only a frame or frameset? Yes, it will save you money. I address this first because most people want to know the bottom-line. You save money. Whether it is worth it or not you should be able to decide by asking yourself a few of the following questions.
But before the questions, lets take a look at how to build a bike. So you're totally stoked you have the frame/frameset that you bought on Ebay or elsewhere, Great!! You should be! Building a bike can be a greatly rewarding and educating experience.
Get used to the fact right now that your frame will have its own specific measurements from the headset, to the seatpost, to the front derailleur, the English/Italian BB (bottom bracket) threading and wheel size. You CAN NOT just go out and blindly buy things you like just by looking at them. YOU MUST consider the sizing otherwise the parts you buy will not be congruent with the frame you have! And if/when you do this, you will be relisting the items or giving them away or worse--end up causing damage to your new frame!
...read the full guide with pics here