How to handle popup using Selenium RC?

Handling Popup's using Selenium RC:

public void testPopup() throws Exception {
    selenium.open("http://yoursitename/page.jsp");
    selenium.click("//img[@alt='Share']");
    selenium.waitForPopUp("_blank", "30000");
    selenium.selectWindow("windowId");
    verifyTrue(selenium.isTextPresent("Recommend to a friend"));
    selenium.close();

}