I've fixed it before, yes. It's a problem known to plague HP/Compaq systems, though eventually it will happen with any of them if the jack gets enough abuse.
You usually need to get a new power jack for your laptop, take your laptop apart, unsolder the old jack, and solder the new one back in. How long this takes depends on how disassemble-unfriendly the laptop in question is. Sometimes all you need to do is bend something, but compared with the frustration of completely disassembling and reassembling a laptop, $40 and a bit of soldering is rather paltry in comparison.
It's really not fun, at all. Then again my memories may be tainted by the first customer I fixed it for.
Depending on the type of jack in question, you can extend the life of the jack through various means, but I'd hesitate to recommend anything without seeing it clearly. The most reliable solution is: simply stop the abuse of it - no more plugging/unplugging, try not to twist it too much if at all possible.