On CentOS 6, EPEL and Remi repo's configged:

[root@localhost]# uname -a
Linux localhost.localdomain 2.6.32-220.4.2.el6.x86_64 #1 SMP Tue Feb 14 04:00:16 GMT 2012 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost]# yum install php-mcrypt.x86_64
Loaded plugins: fastestmirror, priorities
Loading mirror speeds from cached hostfile
* base: centos.mirror.transip.nl
* epel: mirror01.th.ifl.net
* extras: centos.mirror.transip.nl
* remi: remi-mirror.dedipower.com
* updates: mirror.netcologne.de
157 packages excluded due to repository priority protections
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package php-mcrypt.x86_64 0:5.3.11-1.el6.remi will be installed
--> Processing Dependency: php-common(x86-64) = 5.3.11-1.el6.remi for package: php-mcrypt-5.3.11-1.el6.remi.x86_64
--> Processing Dependency: libmcrypt.so.4()(64bit) for package: php-mcrypt-5.3.11-1.el6.remi.x86_64
--> Running transaction check
---> Package libmcrypt.x86_64 0:2.5.8-9.el6 will be installed
---> Package php-mcrypt.x86_64 0:5.3.11-1.el6.remi will be installed
--> Processing Dependency: php-common(x86-64) = 5.3.11-1.el6.remi for package: php-mcrypt-5.3.11-1.el6.remi.x86_64
--> Finished Dependency Resolution
Error: Package: php-mcrypt-5.3.11-1.el6.remi.x86_64 (remi)
           Requires: php-common(x86-64) = 5.3.11-1.el6.remi
           Installed: php-common-5.3.3-3.el6_2.6.x86_64 (@updates)
               php-common(x86-64) = 5.3.3-3.el6_2.6
           Available: php-common-5.3.3-3.el6_1.3.x86_64 (base)
               php-common(x86-64) = 5.3.3-3.el6_1.3
           Available: php-common-5.3.3-3.el6_2.5.x86_64 (updates)
               php-common(x86-64) = 5.3.3-3.el6_2.5
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest

Any ideas?

Thanks in advance,
Alex