Here are 4 more that I'd love to see stickied. I'm sure a lot of people would be interested in these 4 additional how-to guides and I think they are all worthy of being added to the sticky so that people can see them in the future. If you want you may add them to the how-to guide at your discretion Ike. Thanks for the already great post!

-Montrat
Using POP3 email on a network that requires a domain.
If your network involves a specific domain for your email (like if you're on a university campus and your email domain is 'students' --or if your email requires any form of domain like for hotpop) and you cant seem to get your email to work correctly then try this alternative configuration.
Instead of putting in your username and password in the username and password setup screen (screen 2 of 4 in setup) and then putting the domain in the domain box (on setup screen 4 of 4) put the domain followed by a backslash in front of the username on setup page 2.
Example:
User Name: domain\yourusername
Pasword: your password
Then when you get to page 4 fill in the server informaion but leave the domain blank. If you couldn’t get your email to work before this often solves the problem.
Increasing internet performance. (X3i Only)
If the slowness of PIE is driving you nuts you can nearly double its speed by increasing the glyph cache and the TCP window size. This will dramatically improve internet explorer performance without the harmful side effects of overclocking. This setting change will also improve the performance of many graphic-intensive applications (such as games or emulators).
This link is to a free utility that will allow you to increase the size of these memory caches and nearly double the speed of your internet browsing. The only drawback is that doing this requires more memory so if you have a lot of programs installed to the main memory you will see no performance improvement. To install just copy the cab file to your Axim and then load it from there. It's called RegKing 2003. This setting change will not harm your Axim in any way, but as with any utility that makes registry changes it’s always a good idea to make a backup of your data before trying it out.
This is the link to the site:
http://www.cewindows.net/applications/regking.htm
This is the direct link to the download for an X3i running PPC 2003:
http://www.doctorce.com/downloads/RegKing2003ARM.CAB
*Note brought to my attention by Ike: I forgot to mention this. An iPaq and some other PDA's are already at this setting by default. iPaq users need not change this setting, only X3i users will see a speed increase --and the increase will make the X3i perform like it should. --Like an iPaq! LOL
Watching TV on your Axim using wifi + video adapter on your computer.
I saw this in the video section and can't believe I didn't read it in here first. Watch TV on your PocketPC WiFi style! Look mom, no wires. All you need is a PC with a TV/capture card and a wireless connection.
Here are the details:
1) For starters you need to download Windows media encoder 9 and the one for windows media encoder 8 utility right below on the same page at Microsoft Encoders from Pulldown menu link
2) Install 9 then 8 utility.
3) Now once everything is installed open up Windows media encoder, and a wizard will pop up. Choose CUSTOM SESSION
4) first box you will pick your devices by clicking the configure boxes,(this varries from system to system, TV card and Sound card) then click apply.
5) Next tab COMPRESSION under Destination , choose Pocket Pc ,skip down to Audio and choose Voice Quality audio CBR
6) now click the Edit button up by the Destination part and make sure you see WM audio 9 and WM video V8. Now click OK then Apply.
7) All changes now in place You should have Video and Sound. Now what you need to do is click the Start Encoding button at the top.
8) To beem it to your PDA you will need the LAN address or Internet address off of the Connections tab below the video window. Just open up WMP on your AX and choose tools , then open URL type in the address that you got from WM encoder.
Viola! Watching TV on your Axim.
I take zero credit for this. The original post is located Original Thread in Video Section My hats off to bigds63 for the original instructions.
Link to step by step with screen shotinstructions
* Attributed to MMMMMike and bigds63
Mapping a Network drive
There are 3 ways to get something off of a network drive using a PocketPC:
1. the first way is simply using your file explorer or PIE and typing in the address \\server\folder. Using this method you have access to the file and can copy it or move it but you cannot launch or open it. You must copy it to your pocket pc before you can use it.
2. The second way is to use this little free utility
http://www.pocketpcfreewares.com/index.php?soft=504 this is an excellent little freebie program (tested and safe) that will allow you to map a network drive and open files remotely. This utility also has the option to remember your network passwords. This is a great way to stream mp3’s or video files over your network without having to copy them to your Pocket PC first.
3. The third way is the best way but it is not free. Resco File Explorer will map a network drive as well as give you the best file utility available for the PocetPC for about $ 25. If you are a heavy network user and need a way to more effectively manage your files this is the utility for you.
http://www.resco-net.com/explorer.asp