Yes there is, but this involves VBA. If you right-click on the sheet tab name where you want this to happen, choose View Code and then paste the following code into the worksheet module that will open:
<font face=Courier New><SPAN style="color:#00007F">Private</SPAN> <SPAN style="color:#00007F">Sub</SPAN> Worksheet_Change(<SPAN style="color:#00007F">ByVal</SPAN> Target <SPAN style="color:#00007F">As</SPAN> Range)
<SPAN style="color:#00007F">Dim</SPAN> s <SPAN style="color:#00007F">As</SPAN> <SPAN style="color:#00007F">String</SPAN>
<SPAN style="color:#00007F">If</SPAN> Target.Count > 1 <SPAN style="color:#00007F">Then</SPAN> <SPAN style="color:#00007F">Exit</SPAN> <SPAN style="color:#00007F">Sub</SPAN>
<SPAN style="color:#00007F">If</SPAN> <SPAN style="color:#00007F">Not</SPAN> Intersect(Target, Range("A:A")) <SPAN style="color:#00007F">Is</SPAN> <SPAN style="color:#00007F">Nothing</SPAN> <SPAN style="color:#00007F">Then</SPAN>
Application.EnableEvents = <SPAN style="color:#00007F">False</SPAN>
s = Format(Target.Value, "000000")
Target.Value = (CDbl(Right$(s, 2)) / 100) + CDbl(Mid$(s, Len(s) - 3, 2)) + (CDbl(Left$(s, Len(s) - 4)) * 60)
Application.EnableEvents = <SPAN style="color:#00007F">True</SPAN>
<SPAN style="color:#00007F">End</SPAN> <SPAN style="color:#00007F">If</SPAN>
<SPAN style="color:#00007F">End</SPAN> <SPAN style="color:#00007F">Sub</SPAN></FONT>
This will automatically cahnge the value enetered into the A column from format "034555" say to its respective value in seconds (ie 225.55 in this case). Note that there is hardly any error checking involved here, so if somebody were to entrer text instead (ray "Richard" for example) then the code will bug out and report an error. Let me know what you think.