I got no response as to an outlook express or thunderbird option, so I wrote some code to handle thunderbird.
This code will handle multiple address books, includes an outlook express one imported on the thunderbird install, and even checks for duplicates.
If you notice some inefficient code, feel free to let me know... I hope this helps someone who may want to do this at some point.

CREATE CURSOR contact;
 (email c(75))

#INCLUDE main.h
profilepath = SYSTEMPATHS(CSIDL_APPDATA)+"\thunderbird\profiles.ini"
*profilepath = "C:\Documents and Settings\kevin\Application Data\Thunderbird\profiles.ini"
xxx = FILETOSTR(profilepath)

zzz = ATC('Path=',xxx)

thunderbirdpath = ALLTRIM(STRTRAN(SUBSTR(xxx,zzz+5,100),CHR(13)+CHR(10)," "))

CD &thunderbirdpath

seedfile = SYS(2000,'*.mab')
filetest = ADDBS(thunderbirdpath)+seedfile

DO WHILE LEN(ALLTRIM(seedfile)) <> 0  &&& IF there is an address book file
		test = filetostr(filetest)

	x = 1

	DO WHILE AT("@",test,x) > 0 .and. AT("@",test,x)+5 < LEN(test)
		IF !EMPTY(SUBSTR(test,AT("@",test,x)-1,1))
			startat = 2
			DO WHILE SUBSTR(test,AT("@",test,x)-(startat+1),1) <> "="
				startat = startat + 1
			ENDDO

			endat = 2
			DO WHILE RIGHT(SUBSTR(test,AT("@",test,x)-startat+1,startat+endat),1) <> ")"
				endat = endat + 1
			ENDDO	
				
			address = SUBSTR(test,AT("@",test,x)-startat,startat+endat)

			dupe = 'N'
			SELECT contact
			GO top
			DO WHILE .not. EOF()
					IF ALLTRIM(UPPER(address)) == ALLTRIM(upper(contact.email))
						dupe = 'Y'	
					ENDIF	
				SELECT contact
				SKIP
			ENDDO
					IF dupe = 'N'
						IF ATC('$',address) = 0
							INSERT INTO contact VALUES (address)
						ENDIF
					ENDIF
		ENDIF
			x = x + 1
	ENDDO

seedfile = SYS(2000,'*.mab',1)
filetest = ADDBS(thunderbirdpath)+seedfile

ENDDO

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