There's no real difference between cooling an LGA771 and cooling any other CPU in practice since most CPU's under water get overclocked and a voltage bump as a general rule.
So, watercooling the system is down to available space, radiator options and whether you want to cool the sockets
in serial or parallel. Parallel (two seperate loops) may be the preferable option if you're limited to multiple single fan (and hence single 120/140mm radiators) chassis. A
combined reservoir with pump would help if you're space constrained.
As for waterblocks, I'd recommend Swiftech's Apogee series (
XT and
GTZ, which are about as good as it gets for LGA775/771. The added advantages are that 1. if you upgrade the system then then there are mounting and hold-down plates available for LGA1155/1156, 1366 and 2011 sockets, and
2. Being primarily associated with LGA775, they can can be bought relatively cheaply ( The GTZ and XT have been superceded by
HD, which also supports LGA771).
For a more tailored solution I'd suggest you post a link to the chassis you're using (+ any modifications made), budget, hardware purchasing options (i.e
FrozenCPU,
SpecialTech,
Sidewinder,
Performance PC's, and
OnlineComponents (for fans) etc. - I've used all of these suppliers and found all to be very good), and any other considerations (low noise fans for example).