Many tools do many things- there is no one all encompassing tool or set thereof though.
However Megaman zero collection we were playing with earlier today, I warn you though it is perhaps not quite suited to a first hack unless you already know what you are doing:
http://pix.gbatemp.net/32303/demomegamanzerocol2.JPG
http://pix.gbatemp.net/32303/demomegamanzerocol.JPG
As you can see overlay9_0000 is where that was at (credits and menu related stuff by the looks of things)- it is compressed but crystaltile2 made short work of that (right click and press use the extract(U) option).
Thread on the new crystaltile2:
http://gbatemp.net/t232718-crystaltile2-2010-06-12
I mirrored it on filetrip earlier as well
http://filetrip.net/f11824-CrystalTile2-2010-06-12.html
It is a custom table (I am still not sure if it is two tables) but it is relative text making it fairly easy to make a new one.
Tables are simple enough- just past the codebox sections into a blank text file and save with extension .tbl
CODE05=A
06=B
07=C
08=D
09=E
0A=F
0B=G
0C=H
0D=I
0E=J
0F=K
10=L
11=M
12=N
13=O
14=P
15=Q
16=R
17=S
18=T
19=U
1A=V
1B=W
1C=X
1D=Y
1E=Z
25=a
26=b
27=c
28=d
29=e
2A=f
2B=g
2C=h
2D=i
2E=j
2F=k
30=l
31=m
32=n
33=o
34=p
35=q
36=r
37=s
38=t
39=u
3A=v
3B=w
3C=x
3D=y
3E=z
CODE05=A
06=B
07=C
08=D
09=E
0A=F
0B=G
0C=H
0D=I
0E=J
0F=K
10=L
11=M
12=N
13=O
14=P
15=Q
16=R
17=S
18=T
19=U
1A=V
1B=W
1C=X
1D=Y
1E=Z
25=a
26=b
27=c
28=d
29=e
2A=f
2B=g
2C=h
2D=i
2E=j
2F=k
30=l
31=m
32=n
33=o
34=p
35=q
36=r
37=s
38=t
39=u
3A=v
3B=w
3C=x
3D=y
3E=z
You might also want to speak to LuigiBlood who is doing a French translation over at
http://gbatemp.net/t233017-megaman-zero-co...nch-translation . No sense in replicating work if you do not have to.