These are Pendraken Warrior Aliens in 10mm but easily used for 15mm aliens. The pics are slightly out of date, they've really picked up over the last few shows and I've only got a hand full left.
There are four variants of the medium sized aliens and one small type.
Here's a pic of one pack of each code, minus on of the medium warrior codes.
Finally a close up of the queen model, about 20mm tall.
I plan on ordering more from Pendraken to paint for sale at next year's shows both as single bases (maybe on movie style wasteland bases) and on Flames of War bases for things like Future War Commander. If anyone reading would like some get in contact with me. Queens are $3 USD each, all others are $2 USD each.