[Windows Phone 7 Development and Hacking] wm.andrew.wilson:
Thought I would write a thread showing how to simply complete an unlock with Chevron WP7 and some common homebrew apps/tweaks for all platforms. The information is scattered and varied, but I will edit this post to be as useful as possible for beginners as a one stop source. Thanks to the following threads for info:

http://xdaforums.com/showthread.php?t=857127

http://xdaforums.com/showthread.php?t=907971

http://xdaforums.com/showthread.php?t=924497

Unlocking with Chevron WP7

The first step to "sideloading" applications to your phone (applications not approved by Microsoft) is to developer unlock your device.

Downloads needed:

Windows Phone 7 Developer Tools (annoyingly large, but necessary)

Chevron WP7 Application, Chevron Security Certificate, Chevron Registry Entry

TCPView for Windows (don't neglect this, it saves a lot of time and is a useful utility!)

Steps for unlocking:

Install Windows Phone 7 Developer tools. This will require a reboot at the end.

Email the "ChevronWP7.cer" file to your Windows Phone 7 device.

Open the email, tap on the attachment to download it. The icon will turn into a shield, tap again to get a new dialog. Press "Install" then OK.

Put your WP7 Phone into airplane mode (Settings>Airplane mode>Slide the toggle to ON)

Double click the ChevronWP7.reg file on your computer. A prompt will open up asking if you want to write this to your registry. Press Yes to continue, then OK at the end.

Open TCPView. (tcpview.exe inside of the downloaded archive) Click on the heading marked "Local Port" until the arrow next to it is pointing up.

Look on the Local Port column for any entries labeled "HTTPS". These programs MUST be closed for Chevron to work properly. Common culprits are Skype, and XAMPP. Use Task Manager (CTRL+ALT+Delete) to ensure they are closed if you run into issues.

Connect your phone to your PC via USB cable. Open the Zune software if it is not already open, and wait for it to finish syncing.

Open your Zune software and go to the Phone page, and make SURE you don't see anything that denotes that you are in a "Guest Sync" relationship with the device. It needs to be the primary computer the phone is synced with.

Unlock your phone and leave it at the home screen. Make sure the phone does not go to sleep after this.

Open ChevronWP7.exe. It should be running as administrator. Check both boxes, and press Unlock.

Cross your fingers, and you should be up and running on a developer unlocked device! (The Unlock button will change to Relock in Chevron if this is successful)

If you receive the error "Phone is locked with a PIN", it means your phone was locked when the fix was being applied. Make sure to unlock your phone (so you can see the live tiles) BEFORE pressing the unlock button.

If the program crashes, navigate to C:\Windows\system32\Drivers\etc and right click the file named hosts and press properties. Uncheck read only and press OK, then try again.

Homebrew Applications

All homebrew applications are installed as follows:

Go to Start>Programs>Windows Phone Developer Tools> and run Application Deployment

Ensure the target is "Windows Phone 7 Device"

Browse to the .XAP that you are loading.

Connect your phone, wait for Zune sync to finish. Ensure it is not guest.

Unlock phone and keep it awake. Press "Deploy" and the application should load (not extremely fast, and will appear in your app list without a reboot when done)

If the above doesn't work, then try resetting your phone and retrying. Also, restart your computer if the problem persists.

Registry Editor

DO NOT MESS WITH THE REGISTRY UNLESS YOU KNOW WHAT YOU ARE DOING!!!

Registry Editor for all devices (also has a download for TouchXplorer - a file manager for HTC phones only): http://forum.touchxperience.com/viewtopic.php?f=20&t=593 thanks to TouchXperience user schaps for this download.

Great thread on what registry tweaks are currently known: http://xdaforums.com/showthread.php?t=907971

Ringtone Installer

Instructions and XAP downloads at the following link: http://www.chevronwp7.com/post/2054291102/chevronwp7-custom-ringtone-manager

Thanks to the Chevron WP7 team for this app.

Theme Color Changer

Instructions and XAP downloads at the following link:

http://www.daveamenta.com/2011-01/change-accent-colors-on-windows-phone-7-samsung-devices/

Thanks to Dave Amenta for this great app!

Prevent Phone from Relocking

The phone is unlocked, but will relock every time it syncs to Zune unless one of these hacks are done.

Samsung Devices (also removes sideload limit, fixes MMS/data on unlocked phones!):http://xdaforums.com/attachment.php?attachmentid=498084&d=1295825731 from this great thread by lyriquidperfection

All other devices:

In an installed registry editor, navigate to the following key and change these values.

[HKEY_LOCAL_MACHINE\Software\Microsoft\DeviceReg]
"PortalUrlProd"=""
"PortalUrlInt"=""

Let me know if anything should be added or if you need any help! :D