The gchol function in library(kinship) does an LDL decomposition. An updated version has just recently been posted on Rforge, in the bdsmatrix library which is part of survival.
temp <- matrix(c(1,1,1,1,5,8,1,8,14), 3) gt <- gchol(temp)
as.matrix(gt) # L
[,1] [,2] [,3] [1,] 1 0.00 0 [2,] 1 1.00 0 [3,] 1 1.75 1
diag(gt) # D
[1] 1.00 4.00 0.75 Terry Therneau