1、右击桌面的我的电脑 -> 高级 -> 环境变量，新建
1) 变量名：ORACLE_HOME
变量值：D:\app\instantclient_11_2
2) 变量名：TNS_ADMIN
变量值：SIMPLIFIED CHINESE_CHINA.ZHS16GBK
3) 变量名：NLS_LANG
变量值：SIMPLIFIED CHINESE_CHINA.ZHS16GBK
4) 修改Path变量，在最后面添加D:\app\instantclient_11_2 （打开path编辑，最后面加上;D:\app\instantclient_11_2，
“;”用来分隔和前面的字段）

2、在D:\app\instantclient_11_2 目录下新建一个tnsnames.ora文件，添加内容如下
LISTENER_ZHQUAN =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.3)(PORT = 1522))

LISTENER_ORCL =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.3)(PORT = 1522))

ORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.3)(PORT = 1522))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl.redhat)
)
)

ZHQUAN =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.3)(PORT = 1522))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = zhquan.redhat)
)
)

3、至此，oracle客户端配置完毕，你可以直接通过PL/SQL Developer这样的客户端软件来连接数据库

http://pan.baidu.com/share/link?shareid=1528306866&uk=2484678268

也可以下载一个
Instant Client Package - SQL*Plus（第3步的页面下载），解压到D:\app\instantclient_11_2中，即可用 SQL*Plus登录数据库。