the answers to the questions are as folllows
1)jumpers are used on hard drives and optical drives(dvd,cd-roms) and are used to set the drives at master,slave,cable select....a standard hard drive will be set at master,and when you add a 2nd it will be set at slave...the same applies to a dvd/cd-rom ...a 2nd drive will be set at slave......cable select will automatically configure itself to fit your system
2) to buy the right parts you need to get 1.a processor(amd/intel) and 2.motherboard with a socket(or slot) that is compatible with the processor you have bought...i.e sockets a,775,754,939,478
you will need to buy a compatible hard drive ,udma(standard 20 pin connector) or ata (small red 4 pin high speed connector)
graphic card...check your motherboard for slot...agp normally brown with a 2 slot one small one medium....or pci expresss ....many colours longer than agp and a long slot and a smaller end slot.....for more advice consult motherboard manual
optical drives....buy a dvd-rw as this is backward compatible with all other formats(cd-r/rw...dvd-r/rw) 1 drive will do all formats but add a dvd-rom drive(2nd drive set at slave setting) for easier copying of disks
ram....the more the better...recommend at least 512mb but if you can afford 1gb this would be better....comes in different types...ddr,ddr2,sd-ram.....yours will probally take ddr(double data rate)2...comes in different frequency,s 266,333,400mhz
case+psu(power supply unit) case is up to your tastes,but recommended cpu is 350w +,this is important if you need to connect any more devices
modem and network card(ethernet) uf you use broadband a ethernet card is needed(but you will get one on your motherboard)
3) you can buy a anti-static band at any good computer retailer or pc-world(http://www.pcworld.co.uk/index.php?camp_id=ppc_overture_pc_world&ovmkt=64MEFNUOOR1BOM2RFQ99022QNS
4)good processors to use in a build are intel celerons and amd semprons...these are very cheap but can do anything you throw at them...celerons can have clock speeds of up to 3.0ghz and semprons up to 2.2ghz...plenty fast enough...if money is no object go for amd athlon64 and pentium 4 or d
5) a good basic shopping list for a build
processor celeron (intel) =£50
motherboard(socket 775) = £45
40gb hard drive(udma)= =£35
512mb ddr2 ram =£60
dvd-rw drive =£40
graphic card(ati x1600) =£105
case/psu =£60
sound(sounblaster audigy)=£28
this is only a basic list but as you can see it dosent cost that much to build a p.c and its much more fun buiding a pc yourself,i should know ,i built the one i am using at the moment last week,so just be confident in your work,and more imprtant"take your time!"
good luck