Gizmodo has a detailed walkthrough that guides you through the process of getting homebrew apps running on the PSP Slim (or any PSP, really). They skip the whole step of enabling service mode on your battery, since there are some cheap service mode batteries available for $25 that will save you the effort.

When you've completed the walkthrough, you'll have the latest hacked firmware installed which will allow you to run homebrew apps designed for the PSP, as well as any old PS1 games that you own and care to rip.

How To Hack Your PSP Slim For Homebrew Apps

The PSP hackers over at noobz.eu have released a killer tool for fixing any bricked PSP, restoring it to v1.5 firmware. When the PSP boots, the hardware checks for the serial number on the battery eeprom. If it's 0xFFFFFF, it loads firmware from the memory stick instead of from internal flash. You use a working PSP along with the Noobz team's tool to create one of these special batteries. With it, operation can be restored on devices that were previously unbootable due to corrupted firmware. It's also a nice way to completely downgrade your PSP. Pretty cool stuff.

Pandora's Battery: unbricker, downgrader for all PSP firmware versions - Link

A firmware downgrader for version 3.50 of the Play Station Portable firmware was just released today! It makes use of an exploit that was recently discovered in the Lumines game, which you'll have to buy a copy of to make it work. This means that anyone with v3.50 or lower firmware (currently everyone) can now run homebrew games and software (including Linux) on the PSP.

Note that until a firmware revert tool is developed, users with TA-082 or later motherboards will be unable to update to the latest official Sony firmware after this patch is applied.

Downgrader for PSP v3.50 firmware - Link

Here's an online service that will transcode FLVs for you into several common formats, such as AVI/DivX, MOV/MPEG4, 3GP, etc. I've only had a chance to try it on a couple videos, but it seems to work well. You can submit a YouTube URL or a direct link to an FLV and it will kick out a recompressed version that you can easily play on your desktop, iPod or PSP. -Link.

They've also released the trasncoder source under the LGPL, which you can grab over at sourceforge and use in your own transcoding project. Nice! -Link.

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