I think it was around episode 25.
Yes, twice. The first time is in episode 35 of Inuyasha and the second time is episode 9 of "Inuyasha: The Final Act"...is Rin revived? Not telling. Watch and find out ;)
Inuyasha movie 1
I am pretty sure you are talking about Inuyasha: The Final Act episode 18.
It has been out, however the title is called "Inuyasha: The Final Act Episode 1" The official site is shown on the related links.
inuyasha episode 128
He comes on the show in episode 8 or 9.
Episode 18 of InuYasha the final Act
the very last episode in the final act
Episode 97 of Inuyasha: Kirara, Come Home! doesn't actually say when InuYasha practices the Wind Scar on Kirara, but from looking at the flashback when Shippo points out various things Inuyasha has done to Kirara; this leads me to believe that this may have happened in Episode 36 of InuYasha: "Kagome Kidnapped by Koga, The Wolf-Demon".
the inuyasha movie is not an episode
episode 100
of course. they are carring on right now theres episode 168 in japanese.