Once you get to the final area of the game, and if you're around SL 80 - 90, you can find a lot of PVP going there. It's pretty easy to rack up 10 Souvenirs of Reprisal in that place, I was able to get 6 in less than an hour.

The other alternative is farming them off the Harpies in the Painted World of Aramis....and that really takes forever

lol Dark Souls techno viking:
http://www.youtube.com/watch?v=sgGWasoiIIg

here's the original video it's imitating:
http://www.youtube.com/watch?v=yf54VL10gGE

I´m now in what looks like a church, in Undead Parish...just defeated a big black knight that was guarding a corpse with an item called 'Fire Keeper Soul'...it says 'boosts power of Estus Flask"...how does it work and what does it do exactly?...does my HP restoration get better?...is the effect permanent?

Each Fire Keeper soul boosts your Flasks restoration capacities by +1 (aprox extra 100 HP). To make that effect viable, you'll need to bring that soul to any Fire keepr in the game, such as the one on Firelink Shrine, on the bottom of the stairs next to the bonfire. They'll have an option called Reinforce Estus Flasks, use that and they'll be reinforced. 

You can only reinforce them to +7 though.

so just defeated Seath, he wasnt too hard i just used my pyromancys they finished him off quite quck.
just Gravelord nito to go and then its off to the lord vessel to fill it with the souls!

Ok, so when I do that, the effect is permanent, right?...for the rest of the game, whenever I use a Flask, I gain back more health than before, right?

And lestat, another thing, in that same church, I freed a knight named Lautrec...then I found him on Firelink Shrine and he gave me a Sunlight Medal as reward for freeing him..I´m not exactly sure what this medal is for, could you help me out here?

Yeah, it's permanent. You'll keep gaining Fire Keeper Souls through the game, even if your flask is already at +7, but those souls are good for humanity (each gives 5) or for souls (Frampt eats them for 10000 souls).

The Sunlight medals are for levelling up the Warriors of Sunlight Covenant. To take part of that covenant you either got to have 50 Faith, or for each time you help some other player, as a white phantom, defeating any boss, the requirements of Faith drop by 5 points. Also, the place where you can make the covenant pact is located on the portion of the parish protected by the Red Dragon, so you'll have to take him out (or manage to run under him) to get there. 

Also, pay attention to Lautrec's quest line, it'll be important in the future.

Wow I just went farming for Eyes of Death. I got 6 of them in an hour. Guides said 1 per hour if your lucky. Apparently i'm special.

Eyes drop rather fast from the Basiliks on the Great Hollow. I got 5 of them in less than an hour. 

It seems the guide is wrong in a lot of things. It's also wrong in the weapon's list needed for the Knight's Honour trophy.

I did mine in The Depths and was using bones to warp back to the fire.