There is currently no way to download it due to the DMCA takedowns of Bukkit.
However, here are the latest links:
The download page is still here, but does not have any downloads as they are removed due to the DMCA takedown.
Am update posted on the 2nd of December, stating that the project will be reopened, using a completely new fork of the Bukkit project (thus using mainly original code, and not those of which infringed the copyright of Wesley Wolfe.
For now, a backup download page have been created at http://minecraft.maeyanie.com/cauldron/, which may not avaliable in the future. (At the time of this post, it is.)
If you have found any other download source, be sure to make sure that its checksum matches to which was provided by the developers to avoid downloading one with viruses etc. in it.
http://pastebin.com/vVCUmtYD
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e1df3797ba1aed4c19220902df356fcb maven\net\minecraftforge\cauldron\1.7.10-1.1207.01.198\cauldron-1.7.10-1.1207.01.198-installer-win.exe
3c994c0a9ac5bc785855ea7d7d120ca2 maven\net\minecraftforge\cauldron\1.7.10-1.1207.01.198\cauldron-1.7.10-1.1207.01.198-changelog.txt
32a8d3aa64bcb00bfc98a3c44aa17442 maven\net\minecraftforge\cauldron\1.7.2-1.1147.04.196\cauldron-1.7.2-1.1147.04.196-changelog.txt
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ca45b3cf110759491e41a141b8df3304 maven\net\minecraftforge\cauldron\1.6.4-1.965.21.45\cauldron-1.6.4-1.965.21.45-changelog.txt
dec2723f918878b2cde26d1634d5fb94 maven\net\minecraftforge\cauldron\1.6.4-1.965.21.45\cauldron-1.6.4-1.965.21.45-installer-win.exe
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