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The pixel bender plugin for photoshop cs5 has an oil paint filter.
Its a free download or was Oilpaint Effect in Pixel Bender Plugin for Photoshop CS5 | Adobe Advanced Technology Labs
Download the Pixel Bender Plug-in for Adobe Photoshop CS5 for 32-bit and 64-bit on Macintosh and Windows systems, available on Adobe Labs.
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