base R, unstack
unstack(df, V3 ~ V2)
# a b c
# 1 1 2 3
# 2 3 3 2
This may not be a general solution but works well in this case.
data
df<-structure(list(V1 = structure(c(1L, 1L, 1L, 2L, 2L, 2L), .Label = c("x",
"y"), class = "factor"), V2 = structure(c(1L, 2L, 3L, 1L, 2L,
3L), .Label = c("a", "b", "c"), class = "factor"), V3 = c(1L,
2L, 3L, 3L, 3L, 2L)), .Names = c("V1", "V2", "V3"), class = "data.frame", row.names = c(NA,
-6L))