convert vb8 textboxes to excel 2007 adding always in the same sheet but in next lines

Question

i have a small programe in vb8 and i want to convert my textboxes to excel spreadsheet but i want to add again and again in the same sheet changing lines
example if i write something in line a1,a2,a3 the next click to write in b1,b2,b3 and so on
thank you
memas