One alternative strategy you may want to consider is writing covered calls on the stock you have "just sitting there". This will allow you to earn a return (the premium from the calls) without necessarily having to give up your holding.
As a brief overview, "options" are derivatives that give the holder the right (or option) to buy or sell shares at a specified price. Holders of call options with a strike prike $x on a particular security have the right to purchase that security at the strike price $x. Conversely, holders of put options with a strike price of $x have the right to sell that security at the strike price $x. Always on the other side of a call or put option is a person that has sold the option, which is called "writing" the option. If this person writes a call option, then he will be obligated to sell a certain amount of stock (100 shares per contract) at the strike price if that option is exercised. A writer of a put option will be obligated to by 100 shares per contract at the strike price if that option is exercised.
Covered calls involve writing call contracts on stock that you own. For example, say you own 100 shares of AAPL, and that AAPL is currently trading for $330. You decide to write a Jan 21, 2012 call on these shares at a strike price of $340, earning you a premium of say $300.
Two things can now happen: if the price of AAPL is not at least $340 on January 21, then the options are "out of the money" and will expire unexercised (why exercise an option to buy at $340 when you can buy at the currently cheaper market price?). You keep your AAPL stock plus the $300 premium you earn. If, however, the price of AAPL is greater than $340, the option will be exercised and you will now be required to sell the shares you own at $340. You will earn a return of $10/share ($340-$330), plus the $300 premium from the call option. You still make out in the end, but have unfortunately incurred an opportunity cost, as had you not written the call option you would have been able to sell at the market price, which is higher than the $340 strike price.
Covered calls are considered relatively safe and conservative, however the strategy is most effective for stocks that are expected to stay within a relatively narrow price range for the duration of the contract. They do provide one option of earning additional money on stocks you are currently holding, albeit at the risk of giving up some returns if the stock price rises above the strike price.