please take a look at this.
:: checking dependency
make sure openssl installed on the box
[ linux:~ ] # rpm -qa | grep openssl
libopenssl0_9_8-0.9.8g-47.1
libopenssl-devel-0.9.8g-47.8
openssl-certs-0.9.8g-47.1
openssl-0.9.8g-47.1
:: installing imap for php5 from source
[ linux:download ] # wget ftp://ftp.cac.washington.edu/imap/imap-2007a1.tar.Z
[ linux:download ] # tar -xzf imap-2007a1.tar.Z -C /usr/local/
[ linux:download ] # cd /usr/local/imap-2007a/
[ linux:imap-2007a ] # make slx SSLINCLUDE=/usr/include/openssl/
[ linux:imap-2007a ] # cp /usr/local/imap-2007a/c-client/c-client.a /usr/lib/libc-client.a
[ linux:imap-2007a ] # cp /usr/local/imap-2007a/src/c-client/mail.h /usr/include/
[ linux:imap-2007a ] # cp /usr/local/imap-2007a/src/c-client/rfc822.h /usr/include/
[ linux:imap-2007a ] # cp /usr/local/imap-2007a/c-client/linkage.h /usr/include/
:: [re] compile PHP5 from source
please take a look instructions on build php on centos before do this
[ linux:~ ] # cd download/php-5.3.0/
[ linux:php-5.3.0 ] # ./configure [OtherOptions] --with-imap=/usr/local/imap-2007a --with-imap-ssl=/usr/include/openssl
[ linux:php-5.3.0 ] # make && make install
:: testink
[ linux:php-5.3.0 ] # /usr/local/php5/bin/php -m | grep imap
imap
:: restart Apache Service
[ linux:php-5.3.0 ] # /usr/local/apache2/bin/apachectl stop
[ linux:php-5.3.0 ] # /usr/local/apache2/bin/apachectl start
:: Links
+ googlelinux
+ blackonsole
+ dominionweb
