You can't selectively interpolate some texels and not others.
However, this doesn't have to be a problem. If you make all of your transparent pixels black, and then use the "pre-multiplied alpha" blend mode (i.e. src=1, dst=1-srcAlpha), there won't be any artefacts around the edges.

Interesting, I have the same problem. Please help me understand how it works (I am using pre multiple alpha already).
[attachment=11170:TransparentArtifacts_2012-09-09.jpeg]
It is the sampling from the texture that will get a bad color, isn't it? So a position between a white non transparent pixel and a black transparent pixel would become gray 50% transparent? If so, using pre multiplied alpha won't help as long as the colors are wrong?

There is another possibility: Using mipmaps, but you have to create the mipmaps yourself. That way, you can use an averaging algorithm that ignores transparent pixels.

You can't selectively interpolate some texels and not others.
However, this doesn't have to be a problem. If you make all of your transparent pixels black, and then use the "pre-multiplied alpha" blend mode (i.e. src=1, dst=1-srcAlpha), there won't be any artefacts around the edges.

Interesting, I have the same problem. Please help me understand how it works (I am using pre multiple alpha already).

It is the sampling from the texture that will get a bad color, isn't it? So a position between a white non transparent pixel and a black transparent pixel would become gray 50% transparent? If so, using pre multiplied alpha won't help as long as the colors are wrong?

There is another possibility: Using mipmaps, but you have to create the mipmaps yourself. That way, you can use an averaging algorithm that ignores transparent pixels.
[attachment=11170:TransparentArtifacts_2012-09-09.jpeg]