I found this http://www.php.net/manual/en/class.snmp.php, but I can't find link to download this script. I tryed to search in the WEB, but the same result.
Or is the any methods with php extension to make one session and work with it?
It is in the tarball. You can download it from the official website
Take a look into it:
$ tar jtf php-5.4.13.tar.bz2 | grep snmp
php-5.4.13/ext/snmp/
php-5.4.13/ext/snmp/config.m4
php-5.4.13/ext/snmp/config.w32
php-5.4.13/ext/snmp/CREDITS
php-5.4.13/ext/snmp/php_snmp.h
php-5.4.13/ext/snmp/snmp.c
php-5.4.13/ext/snmp/snmp.dsp
php-5.4.13/ext/snmp/tests/
php-5.4.13/ext/snmp/tests/bug60749.phpt
php-5.4.13/ext/snmp/tests/bug64124.phpt
php-5.4.13/ext/snmp/tests/clean.inc
php-5.4.13/ext/snmp/tests/generic_timeout_error.phpt
php-5.4.13/ext/snmp/tests/ipv6.phpt
php-5.4.13/ext/snmp/tests/README
php-5.4.13/ext/snmp/tests/skipif.inc
php-5.4.13/ext/snmp/tests/snmp-object-errno-errstr.phpt
php-5.4.13/ext/snmp/tests/snmp-object-error.phpt
php-5.4.13/ext/snmp/tests/snmp-object-properties.phpt
php-5.4.13/ext/snmp/tests/snmp-object-setSecurity_error.phpt
php-5.4.13/ext/snmp/tests/snmp-object.phpt
php-5.4.13/ext/snmp/tests/snmp2_get.phpt
php-5.4.13/ext/snmp/tests/snmp2_getnext.phpt
php-5.4.13/ext/snmp/tests/snmp2_real_walk.phpt
php-5.4.13/ext/snmp/tests/snmp2_set-nomib.phpt
php-5.4.13/ext/snmp/tests/snmp2_set.phpt
php-5.4.13/ext/snmp/tests/snmp2_walk.phpt
php-5.4.13/ext/snmp/tests/snmp3-error.phpt
php-5.4.13/ext/snmp/tests/snmp3.phpt
php-5.4.13/ext/snmp/tests/snmp_get_quick_print.phpt
php-5.4.13/ext/snmp/tests/snmp_get_valueretrieval.phpt
php-5.4.13/ext/snmp/tests/snmp_getvalue.phpt
php-5.4.13/ext/snmp/tests/snmp_include.inc
php-5.4.13/ext/snmp/tests/snmp_read_mib.phpt
php-5.4.13/ext/snmp/tests/snmp_set_enum_print.phpt
php-5.4.13/ext/snmp/tests/snmp_set_oid_output_format.phpt
php-5.4.13/ext/snmp/tests/snmpd.conf
php-5.4.13/ext/snmp/tests/snmpget.phpt
php-5.4.13/ext/snmp/tests/snmpgetnext.phpt
php-5.4.13/ext/snmp/tests/snmprealwalk.phpt
php-5.4.13/ext/snmp/tests/snmpset-nomib.phpt
php-5.4.13/ext/snmp/tests/snmpset.phpt
php-5.4.13/ext/snmp/tests/snmpwalk.phpt
php-5.4.13/ext/snmp/tests/wrong_hostname.phpt