If I were to attempt this I'd think along these lines:
-Use Substring to get the first character of the string and the rest separated
-Use ToUpperCase on that first substring
-Re-concatenate the two substrings.
I'm thinking the expression would look similar to this (off the top of my head, completely untested, and assuming the substring position counter starts at 0)
$(ToUpperCase(Substring(TextField,0,1)) + Substring(TextField,1))
Jon, One minor change and its a winner
$(ToUpperCase(Substring(TextField,0,1)) + Substring(TextField,2))
Changing the last parameter to 2, prevents duplicating the first letter when concatenating.
Thanks for the assist!