impossible to estimate that. I didn't count the hours / days I worked on it. it has over 50k lines of code though. would take months to recode this for iphone/ipod touch (if you want to have a version with all the features of the original one). I'm surely not going to do that
maybe a much more limited version but I'm currently not planning to spend 100 (?) usd per year just for the chance that the game MIGHT by released in the app store. yeah, you have to pay money to develop games for Apple hardware... Apple is BAD and absolutely not "developer-friendly"
oh and Apple would - of course - absolutely decline a Counter-Strike clone due to licensing/copyright and stuff. this means that it would have to have another name etc.
these things are not as easy as you seem to think