To plot a function from the interval [0,1] to the complex plane using Mathematica 6.0, the recommended approach is to utilize the ParametricPlot function. The syntax involves plotting the real part of the function on the x-axis and the imaginary part on the y-axis, specifically using the command ParametricPlot[{Re[f[x]], Im[f[x]]}, {x, x_i, x_f}]. This effectively visualizes the function in a manner analogous to a complex plane representation. For further details on the functions used, references to Re[], Im[], and ParametricPlot[] are available in the Mathematica documentation.