Dunny is correct with four. All of them were in friendlies and I'm not sure if he actually completed 90 minutes in any of them.
To be honest, his getting capped is as much a tribute to his positive attitude and "stickability" as his ability (imo).
For when Roy Carroll got fed-up being back-up to Maik Taylor and started acting the maggot, Sanchez and Worthington looked at a number of other keepers, none of whom really shone.
Meanwhile, Mannus hung in there, always ready to answer the call, even if it was only to warm the bench.
At present, it looks to be a toss-up between Mannus and Jonathan Tuffey (22 year old at Partick Thistle) as to who is back-up these days. My suspicion is that Mannus may be relegated to 3rd choice, as Tuffey gains more experience, since he (Tuffey) does look to be a prospect?
That said, I'd guess Mannus will do a good job for Shams, since he has the basics and certainly looks to take his football career very seriously.
http://en.wikipedia.org/wiki/Alan_Mannus
http://en.wikipedia.org/wiki/Jonathan_Tuffey