Stem-changing Spanish g>j verbs in the present subjunctive

In Spanish some verbs ending in -ger/-gir undergo a stem change in the present subjunctive, in a very similar way they do in the present indicative. They will switch the -g for -j. The difference is that while in the present indicative only the yo form is affected, in the present subjunctive all forms are affected by this change.
Have a look at these tables showing both the present indicative and the present subjunctive of coger (to take):

	COGER (present indicative)	COGER (present subjunctive)
yo	cojo	coja
tú	coges	cojas
él / ella / usted	coge	coja
nosotros / nosotras	cogemos	cojamos
vosotros / vosotras	cogéis	cojáis
ellos / ellas/ ustedes	cogen	cojan