Creating multiple holes

main page
1). Select all verts where you want a hole to be formed.
2). Appy Edge | Bevel as required (I used 0.2 here)
3). Press E (change to edge mode)
4). Press 2 (Edge | Cut 2 - to cut selected edges in half and place new verts at mid points)
5). Press C ( Connect selected verts with new edges)
6). Press E (Change to edge mode)
7). Press - (minus) to shrink edge selection.
8). Apply Edge | Scale -> Uniform -> 141.42% (press Tab after starting operation and enter amount shown)
9). Press Backspace (Edge | Dissolve, to get rid of unwanted edges)

The above method requires the original edges to be on a flat surface and at right angles to produce the best results (for multiple hole production)
Instead of dissolving the edges selected in (8), it might be an idea to press V (change to vert mode) to leave all newly scaled verts selected.
At this stage, you could then select all other relevant verts (to which they should be connected) and use Vert | Connect - might save a bit of time?
If you're only creating a single hole, skip stages 5 - 8 and just use scale on the 4 verts shown in (4) . You could also use
Vert | Inflate -> 100% (RMB option) for this (single hole case)

Note that selections have to be (unconnected) edge or face ones for multiple (isolated) operations to work correctly around their own selection centres - switching to vert mode will tell Wings to work from a single selection centre (based on all verts selected) - and mess things up - bigtime.

Note that the scaling factor used in (8) is sq root 2 with decimal place shifted. This is well worth remembering (or having handy) imo as it's very useful for many ops in wings.
If you want to create multiple holes - at the same time - and the object / model has suitable attributes, the following method may be useful.

I've demonstrated with a single hole (on a standard grid) for the purposes of clarity and keeping the 'strip' to a manageable size.