[R] scatter plot using ggplot

[Megh Dal]

I used ggplot to create a scatter plot :

library(ggplot)
library(mnormt)
Sigma = matrix(c(1, 0.6, 0.6, 1), 2, 2)
x = rmnorm(20, c(0,0), Sigma)
xx = x[order(x[,1]),]
y = xx[,1]
z = xx[,2]
qplot(z, y, type="point", main="x-y plot", xlab="x", col="blue")

However I want following:

1. Plot color must be Blue (where it is displaying as red)
2. There should not be any color platted
3. Plot size must be larger than what it is displacing

Can anyone please tell me how to do that?

Regards,