http://server5.uploadit.org/files/ConKbotofDoom-hdd.jpg There should be a screw around there under the label, if there is you have to either be careful not to bend that and do a partial window to leave the screw there for strength, or not do it at all. Do laptop hdds typically have a screw there? That might be feasable then.
I must agree with Tomm®. If you're at the stage where a few LEDs seem too complex to you, and you have to ask people where you should cut the lid, then you're not ready to do this. Your question suggests to me you haven't even read the mod guides of similar projects yet (dotted all over the net, just Google), which should be your first port of call. Once you have done that, you should have no further questions but just be able to do it. However, even very experienced modders have had their HDDs die on them. So even if your drive is expendable, don't waste your time and effort --try something more feasible and rewarding.
by the way, I read on some guide that if you don't want to risk it dying but still want a mostly DIY, you can take a useless hard drive, cut the window into it, and have a store swap the parts. I guess it would be hard to find parts that fit but apparently some places have dust free rooms you can do this in. Or you could go to my uncle's workplace at Intel and do the whole mod in their wafer making room
