Semplice prima di tutto devi aver installato php da packege e non da installer dopo di che basta apportare qualche modifica a php.ini:

; Directory in which the loadable extensions (modules) reside.
extension_dir = "C:\percorso alla cartella di php\cartella in cui sono le estensioni\"

poi in questo elenco (sempre in php.ini)
;extension=php_bz2.dll
;extension=php_cpdf.dll
;extension=php_curl.dll
;extension=php_dba.dll
;extension=php_dbase.dll
;extension=php_dbx.dll
;extension=php_exif.dll
;extension=php_fdf.dll
;extension=php_filepro.dll
extension=php_gd2.dll
;extension=php_gettext.dll
;extension=php_ifx.dll
;extension=php_iisfunc.dll
;extension=php_imap.dll
;extension=php_interbase.dll
;extension=php_java.dll
;extension=php_ldap.dll
;extension=php_mbstring.dll
;extension=php_mcrypt.dll
;extension=php_mhash.dll
extension=php_mime_magic.dll
;extension=php_ming.dll
;extension=php_mssql.dll
;extension=php_msql.dll
extension=php_mysql.dll
;extension=php_oci8.dll
;extension=php_openssl.dll
;extension=php_oracle.dll
;extension=php_pdf.dll
;extension=php_pgsql.dll
;extension=php_shmop.dll
;extension=php_snmp.dll
;extension=php_sockets.dll
;extension=php_sybase_ct.dll
;extension=php_tidy.dll
;extension=php_w32api.dll
;extension=php_xmlrpc.dll
;extension=php_xsl.dll
;extension=php_yaz.dll
;extension=php_zip.dll

togli il ; alle estensioni che vuoi caricare... dopo di ch salva e riavvia apache