1 Introduction

Since 1997, we have been monitoring the error boxes of gamma-ray bursts (hereafter GRBs) detected by the BSAX or RXTE satellites. We have monitored 15 GRB fields on the aggregate, detecting 6 optical/IR afterglows. See Castro-Tirado (1999) and Gorosabel (1999) for a review of results. Here we focus on the GRB 970508 and GRB 980326 afterglows.