Here's some info on L-Ion Batteries also check out richduns informative posts below (more helpful)

1. Battery Memory – When I first got my new cellphone, my friend recommended to fully drain the battery before recharging it. His reasoning was connected to the idea of battery memory. Allowing the battery to fully discharge then recharging to max, supposedly gives you the complete battery capacity. Otherwise, if you simply charged from the half way point to max battery capacity, the battery would treat the half way point as the empty point, thus cutting your battery capacity in half.

Problem is battery memory doesn’t apply to lithium batteries, this advice was meant for nickel based batteries. Fully discharging your lithium battery frequently can actually be quite harmful to your battery’s health, possibly rendering it completely unusable if energy levels go too low.

The good news is today’s lithium batteries have a safety circuit in place to insure the battery doesn’t reach the point of no return. The safety circuit isn’t fool proof though, if you leave your battery completely drained for a few days, even the circuit’s protective measures won’t save it.

2. Battery Calibration – There are some benefits to fully discharging your lithium battery periodically, for laptops this can be especially important. If you start to notice your battery meter becoming more and more inaccurate, it may be time for some battery calibration. Allow your lithium battery completely drain, then charge until the battery is full again. This will calibrate your battery  giving you more accurate readings. This should be done once every 30 charges or when you notice battery readings are off.

3. Consequences of Heat – Another enemy of lithium battery life is heat. If you were to leave your laptop plugged in and running for a year, you should expect the lithium battery capacity to be anywhere between 60% to 80% of it’s original max capacity. This is why people that use their laptops as desktop replacements will notice greatly reduced battery life performance after one year of use. This issue can be resolved by removing the battery while using a corded power source. Now you may want to check with your manufacturer ahead of time to check for safety concerns, some manufacturers have mentioned problems such as moisture and dust collecting in the battery casing.

4. Battery Storage – If you don’t plan on using your lithium battery for prolonged periods of time, then you’ll want to reduce the charge level to 40% and place the battery in the fridge (not freezer). Storing the battery at 100% charge level applies unnecessary stress and can cause internal corrosion. On the other hand, if the charge is too low, the battery can become permanently unusable, due to battery self discharge. This is why manufacturers recommend storing your lithium batteries at 40% charge, rather than either extreme.

Source of infprmation: http://osxreality.com/2009/07/18/4-tips-to-extend-your-lithium-battery-life/

Current phone batteries are LIon and do NOT need to be conditioned.  In fact they like to be charged when partially empty.

Your method is used for nicads which haven't been used in phones for years.

:D

D:

I didn't want to get technical but it's in the battery chemistry.  What you are referring to is "memory effect".  That comes form loss of chemical reaction at the molucular level.  In nicad batteries the molucules get old over time and loos their ability to chemically react, gain a charge.  In an Lion battery the cells do not have this molecular property in fact they charge and discharge as a group.

 This is why experts, battery chemists, tell you to chanrge an Lion battery whenever you are near a charger.

That is why when a Lion battery dies it dies all at once not gradually as a nicad battery does.

Condition all you want but you aren't doing your battery any favors.

In case there is any question or confusion here is information form the guys at Battery university:

There is only one way to charge lithium-based batteries. The so-called 'miracle chargers', which claim to restore and prolong batteries, do not exist for lithium chemistries. Neither does super-fast charging apply. Manufacturers of lithium-ion cells have very strict guidelines in charge procedures and the pack should be charged as per the manufacturers "typical" charge technique.

Lithium-ion is a very clean system and does not need priming as nickel-based batteries do. The 1st charge is no different to the 5th or the 50th charge. Stickers instructing to charge the battery for 8 hours or more for the first time may be a leftover from the nickel battery days.

Touche sir I have corrected the post ;)