Do you know any tools that generate electrostatic potential 2d maps of the molecules as an image?
Most computational chemistry software packages geared toward students/education should be able to do this. Examples include Scigress, formerly CAChe, Spartan, which has a 'lite/student' version that can probably do it, etc. Generally, any modeling software, for example, Gaussian or GAMESS should generate a file with the electrostatic potential map provided you give it the correct instructions. The output files of these methods can be visualized using many types of software (like Scigress and Spartan) and open source software like Avogadro.
If you are looking for an inexpensive solution, GAMESS is free for research/education and Avogadro is open source.
As Ben Norris said, there are approximate methods around. But if what you want is a very precise, very reliable electrostatic potential map, you will need to do a quantum chemical calculation to get the electron density. Here is a nice discussion about multiple-derived and charge-based methods versus, say, DFT. There it says:
For example, six slightly negative charges on carbons balanced by six slightly positive charges on hydrogens do a poor job capturing the essence of the negatively charged π cloud above and below the six-membered ring [of benzene]. The image below illustrates electrostatic potential maps for benzene using the true potential, multipole-derived, and charges-based methods.
If you want to generate a electrostatic potential map from a
.wfn file (a very common file type for carrying wave functions around), MultiWFN may be what you want.
MultiWFN helps you analyse the wave function using many different techniques.
It also allows you to visualise both the 3D and the plane projected electrostatic potential map (both colour-coded or contour-mapped I believe).
.wfn file may be generated from a
.gbw file from ORCA using Molden2AIM, for instance.
Molden2AIM can actually convert many wave function output files to
.wfn, so please check it out.
For the particular purpose of using it with ORCA I have written a small program that considers many details and does the job faster than "by hand".
If you want, MultiWFN also generates suitable
.cube files for you.
These are useful for visualising in third party software.
I also wrote a small program that can generate those and write a small VMD script for visualising.
VMD is able to produce publication-quality images.
All tools cited in this post are free to use.