How to calculate Bitcoin address with specific pattern?

[gst]

Is there an existing tool that allows me to calculate my own Bitcoin addresses that include a specific pattern?

Something like khal's addresses here: http://forum.bitcoin.org/index.php?topic=10826.0 (see signature)

I could probably write my own tool for this (brute-force generation of ECDSA keypairs until one matches, and then moving the matching one into my wallet.dat) but it'd be somewhat easier if there would be already existing software for this.

[mewantsbitcoins]

Yes there is - do a search

[Maged]

Yes there is - do a search

The least you can do is give a search term...

Anyway, this is what the OP is looking for:
http://forum.bitcoin.org/index.php?topic=1387.0