VanityGen is the tool for search public and private key pairs with a given prefix in the public key.
Binaries for windows can be downloaded here
There is CPU generator named vanitygen.exe in the archive. It can be used for simple searches. For example, I searched key started with my nick "spin" (4 letter):
C:\vanitygen>vanitygen.exe 1spin
Difficulty: 264104224
Pattern: 1spin
Address: 1spin6S3UTAwu3bxngLrGWfxDZkTSFcSw
Privkey: 5KU....xu8
(All public keys in bitcoin started with "1", so I search "1spin" prefix). The program shows the address and private key (I removed part of the private key from output).
If you have several GPUs, you can use program oclvanitygen.exe. It can search addresses using GPUs. For example, if you have 6 GPUs, you can use the command line like:
C:\vanitygen>oclvanitygen.exe -D 0:0 -D 0:1 -D 0:2 -D 0:3 -D 0:4
-D 0:5 1spiiin
Difficulty: 888446610538
Pattern: 1spiiin
Address: 1spiiinfVdADUh32Ssa7m5V1AvYonTgiq
Privkey: 5Jn...XF9
With this tool, I found several addresses starting with "1JUGGLE":
1JUGGLE54spwsc4SD7tET9dbg8PHDqB5XY
1JUGGLEeSdTZEKNJ3ozUmkkEZECiorTgob
1JUGGLEoUvvtRySNxYkNttKdF3VzkjZxM6
I'll use these bitcoin wallets for juggling quests with prizes in the future.