Aggregation and micelle formation in dilute solutions of amphiphilic oligopeptides (Ala(nH) Asp(nP)) is considered theoretically. It is shown that the peptides can self-assemble forming micelles of different morphologies in the regime where Asp units are negatively charged. The micelles are stable thermodynamically if a sufficient amount of monovalent salt is added (the "salting in" effect). The thermodynamic stability of the micelles also strongly depends on pH and on the size delta of added cations. The micelles get destabilized as their surface charge (due to Asp units) decreases at low pH or low ionic strength I-infinity. A larger cation size delta also results in aggregation (precipitation) of the micelles. The aggregation process can be kinetically arrested clue to electrostatic repulsion even in the regime of weakly charged Asp units. The kinetically defined size R of the aggregates strongly depends on the effective peptide/water interfacial tension gamma and on the Debye length r(D): R decreases as either gamma or r(D) is increased.