"Nintendo controllers have had analog sticks since the N64 but for whatever reason the WiiÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s main controller only includes a D-Pad. (Yes IÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢m aware the Nunchuck has one.) If you miss this feature or your thumbs have been rubbed sore on the WiimoteÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s D-Pad you might want to give this analog stick convertor a shot.
Called the ÃƒÂ¢Ã¢â€šÂ¬Ã‹Å“Remocon StickÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢ it basically sits over the top portion of the Wiimote and turns the D-Pad into a slightly more ergonomic analog controller. While it doesnÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢t provide the precise level of control that the real analog stick on the Nunchuck does it will at least be a bit easier on your thumbs. And at about $6 itÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s not a bank-breaker either." link