The more specific answer that I guess Danny should have given is:
<PropertyGroup Condition="'$(FSharpTargetsPath)' == '' OR (!(Exists('$(FSharpTargetsPath)')))">
<FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Common7\IDE\CommonExtensions\Microsoft\FSharp\Tools\Microsoft.FSharp.Targets</FSharpTargetsPath>
</PropertyGroup>
<PropertyGroup Condition="'$(FSharpTargetsPath)' == '' OR (!(Exists('$(FSharpTargetsPath)')))">
<FSharpTargetsPath>$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)\FSharp\Microsoft.FSharp.Targets</FSharpTargetsPath>
</PropertyGroup>
<PropertyGroup Condition="'$(FSharpTargetsPath)' == '' OR (!(Exists('$(FSharpTargetsPath)')))">
<FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\4.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
</PropertyGroup>
<PropertyGroup Condition="'$(FSharpTargetsPath)' == '' OR (!(Exists('$(FSharpTargetsPath)')))">
<FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.1\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
</PropertyGroup>
<PropertyGroup Condition="'$(FSharpTargetsPath)' == '' OR (!(Exists('$(FSharpTargetsPath)')))">
<FSharpTargetsPath>$(MSBuildExtensionsPath32)\..\Microsoft SDKs\F#\3.0\Framework\v4.0\Microsoft.FSharp.Targets</FSharpTargetsPath>
</PropertyGroup>
<Import Project="$(FSharpTargetsPath)" />
This should work with all versions.