firstly, there is an extrememly easy way but requires you upgrade cpanel using /scripts/upcp
Only thing is, when you do that, you will need to upgrade your kernel and apache (or at least I did) as cpanel says they are insecure and when it says that I get annoyed
Once you have upgraded go down to Software in whm and select Update Apache once there, select Curl (Version 7.10.5) under Perl Module
Otherwise you would need to do it the hard way
http://curl.haxx.se/docs/install.html