Below are sites that deal with mobile phones, have content available for you to download, or contain information that may be useful. If you know of other sites, feel free to email me about them.

Ringers, Wallpapers, and Other Phone Files

Craig Given
Very clean site with ringtones, apps, and images. There is also a very nice FAQ available that will answer many questions about using your phone and getting more things onto it.
fonpirate
Browse this site with your phone to get images, ringers, and programs.
Fresh MIDIs
Popular songs that are in MIDI format, ready for your phone.
MBuzzy
Free ringtones, apps, and images. Lots of content.
Midi Freak
Free MIDI songs, ringtones, and other things you can upload to your phone.
Midlet.org
Java based games for mobile phones.
MyPhoneFiles
Ringers, wallpapers, and more.
phoneART
Collection of wallpapers and ringers for you to download. You can also leave a comment in the guestbook to request something special.
Ring Cities
Forum site where you can get ringers, games, and other downloads.

Other Uploaders

2 ur Phone
An alternate uploader that uses its own custom software. If you try this, let me know how well it works.
3G Inferno
A blended site that hosts both my old and newer uploader, so you can upload .jar files with .jad if you have them.
a9000 Upload
Formats files so you can use QPST to transfer them to your phone with a USB cable. Doesn't do any uploading itself; it helps make the required files to use QPST effectively.
BitPim
Runs on your local computer and talks to your phone through a special USB cable. Freeware, but you do need to go out and buy a cable.
CellPhoto
Another uploader site that was mentioned in the shoutbox.
Chris On The Web
My uploader, but skinned to look better and with an improved gallery.
gtoal.com
An earlier version of my uploader. If you have problems uploading a .jar that you think should work, make sure that you have the .jad handy and try this uploader.
Knuckledragger.net
Another older copy of my uploader. Seems like this free stuff is quite popular.
LiquidFish
Modified copy of a very early version of my uploader.
Lunarnexus
Another mirror of my uploader. Plain looking but that just means it loads faster.
Nexzign
One more copy of the uploader.
PCS.Cruz-Network.net
Same uploader as here, but looks better.
PCSpix
Lets you upload files to your phone after registering. Not sure what uploader software they use.
Pix2Fone
Alternate site that will let you send images to your phone.
ThePhoneMall.net
My uploader that has been spruced up quite a bit.
RingRingFree
Another place that hosts the uploader I wrote.
SigStop
Another copy of the uploader.
SprintUsers.com
Their own software that will send files to your phone. They stole large portions of my FAQ and regurgitated it in their own FAQ. Thanks for the lack of credit.
Stellernet.com
Recently set up and would like users to visit his site.
T1mmy.net
An independantly written piece of software that does a very good job of sending files.
Total Uploader
This file sender appears to use its own code to send images, PRC files, zip files, Java midlets, and plain text messages to phones.
Veracity
Another copy of my uploader.
Vorpal Cloud
Same uploader as me, but themed to go with their site.

Informational Sites and Online Converters

Atlanta Journal-Constitution :: Geekboy
A write-up on how to create and send ringers to your phone.
CMX FAQ
Some information about the CMX format.
Dreampages
A site that lists many other Sprint-related sites.
How to make PMD files from animated GIFs
A step-by-step document with lots of nice pictures.
Online Image Converter
Change your bmp, png, gif, or jpeg images into another type.
Samsung A660 Information
How to get files on your phone, games that work, setting it up as a modem for your computer, and lots of other information.
Screen Sizes
A list of screen sizes so you can resize images to fit your phone before you upload them.
SprintUsers
This is their section for Sprint Vision PCS users. It contains links to many other worthwhile sites.
WAP Universal Resource File
Look up phone information based on model, make, or user agent string.

Uploading and Related Software

BlurredVision
PHP toolkit to upload files to your PCS phone. Still in early development stages.
messaging.inc
PHP function to send a SMS via Sprint's web site. It works better than using email to send messages.
MiniSendNote
Tiny program to send messages from a Sprint phone without forcing you to use their annoying WAP system.
My Uploader
The code that runs this site. Not to be humble, but it has all of the awesome features I can think of. Automatic image resizing, phone detection, and tons more. Oh, it's freeware (open source). Yeah, I know, that wasn't humble at all.
PCS Vision Uploader
Appears to be effectively the same thing as what I wrote, but developed independently.
Text Messenger
Palm OS program to send a Sprint user a message.