I was reading at forums and spotted a thread called 'Balto4!?' I checked it out and this guy said something about Balto 4 being wrote as they spoke.
I thought that he wasn't right.I searched the internet for a long time and couldn't find anything.I don't guess there will be a B4. :(

steet added that on the article :

Mmm, I think I forgot something with sending an article : entering your email...As is, I would have not put this article, because it's more of a topic that ask and don't give information. So I'm gonna complete this a little.
Well, there are no official information that says that there will be a Balto 4. At the moment it's still completly possible that there will be no more Balto sequels (after all, Universal did stop making DTV sequels for An american tail after the second one...)
But, there are also a few things which bring me to think that Universal Home Video will not stop there.

First, two german people sent emails to Universal Germany, and they answered that a Balto 4 would be planned, and they would be waiting for a confirmation. But then, in another email, they said that they didn't know about another sequel for Balto...but a different person from Universal Germany could have answered.
Someone else contacted Universal america, and they said that "they have no release date for more sequels in this franchise".

Second, Balto 3 made fairly good sales. Here are the sales of Balto 3 found on Dvdexclusive.com (these sales are only the sales as of April 16th 2005, and only count the sales made by the Direct-to-video DVDs this year) :

TOP DVD PREMIERE MOVIES: YEAR-TO-DATE
Rank Title (label/distributor) Street Date Revenue
1 MULAN 2 (DIS) 2/1/2005 57.0
2 ALADDIN: 2-3 COLLECTION (DIS) 1/18/2005 18.1
3 BLUE COLLAR COMEDY TOUR RIDES 12/7/2004 15.8
4 BARBIE: FAIRYTOPIA (LG) 3/8/2005 13.0
5 ALOHA, SCOOBY-DOO! (WB) 2/8/2005 11.4
6 LBT: INVASION OF TINYSAURUSES 1/11/2005 10.9
7 LION KING 2 (DIS) 8/31/2004 8.3
8 INTO THE SUN (SONY) 2/15/2005 7.3
9 WAKE OF DEATH (SONY) 12/28/2004 6.4
10 BALTO 3: WINGS OF CHANGE (UNI) 2/1/2005 6.3
11 BARBIE…PRINCESS AND THE PAUPER 9/28/2004 6.1
12 LION KING 1½ (DIS) 2/10/2004 5.9
13 WHERE THE RED FERN GROWS (DIS) 12/21/2004 5.3
14 POKEMON: DESTINY DEOXYS (DIS) 2/15/2005 5.2
15 CONTROL (SONY) 2/16/2005 4.4

Finally, the DTV section for children/family is booming, and Universal made big changes in its "Universal Home Video Family Entertainment" division as an expansion. I will explain that point better in another article.

But, you're right that for the moment, there's no real information, and if there would be another sequel, my guess is that it would be released in 2007, so : wait & see...