I'm not going to go into too much depth about the cable itself just the details about using one,it's a cable!,one end goes in your PS2 the other into your TV's component input.
Using a RGB scart on a LCD TV dosen't give a very good picture,it's very blurry and the colours are way off in some games,it's almost like using the AV cable that came in the box.Once you've set your PS2 to the right setting it will then automatically display in 576i.
The picture is very sharp and the colours and contrast are much better than a RGB on a conventional TV.Here's the pros and cons,On games that can output in progressive scan (Primal,Ghosthunter,Project Zero 3 and a few others)the picture is amazingly sharp and defined with only minimal "jaggies" round the edge of things,On the other hand,some games are very pixellated with the worst offenders I have being:Anything by Free Radical(except Timesplitters 1,TS2 isn't that bad but Future Perfect is awful),Broken Sword(when the characters are very small)and by far is Virtua Fighter 4 which is very jagged on conventional TV but even worse through a LCD/Component cable.
On the whole the picture is much better with most games looking very good,Headhunter:Redemption is incredible and even "oldies"like Deus Ex,Half Life and Red faction look crisp,only few games still retain noticeable "jaggies"
The biggest drawback is that PSone games can no longer be used as they can't display properly,if at all.Even using a RGB scart lead through a LCD TV results in a picture that flickers at the bottom.
Ultimately it's a bit late in the day to be worrying about what a last gen machine(and further back!) looks like through a component cable but it's worth knowing.