Combos
-d.c.LK > c.LK > c.HK XX qcf + LP
-Jump LK > HK \/ d.c.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK, f + HP
-Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK XX f,d,df + P
-Corner qcf + P. Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK XX qcf + P, f,d,df + HP
-Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK > sj.HP
-qcf + P. Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK XX qcf + P, sj.HP
-Corner qcf + KK, d.c.LK > s.HK /\ sj.LP > sj.LK XX qcf + PP
-Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK XX qcf + PP
-qcf + P. Jump LK > HK \/ d.s.LK > s.HK /\ sj.LP > sj.LK > sj.LP > sj.LK XX qcf + P XX qcf + PP
-Hold HP. Jump LK > HK \/ d.s.LP > s.LP XX Release HP XX qcf + KK, d.c.LK > s.HK /\ sj.LP > sj.LK XX qcf + PP
Beat Plane Combos
With the leaf shield: Activate leaf shield, launch, SJ, SJ.LP, SJ.LK, SJ.MP, SJ.MK, release leaf shield, xx Beat Plane .
You can also combo into Beat Plane or Rush Drill off a charged Buster, but there's generally no good reason to do that.
Infinites
MegaMan Steve's Corner Infinite: HK (launch), SJ, LP, LK, MP, air throw, pause, (while falling) SJ LK, (normal jump, J.LP, J.MP, J.FP, land, repeat).
His infinite (J LP, J MP, J FP) isn't really practical outside of the corner. Very few people can do Mega Man's infinite reliably - usually it is best set up off a good assist such as Psylocke, and is best in the corner. Romneto made a tutorial video on Megaman's infinite which can help you understand the pacing.
