DNS resolution Problem from hosts of one forest to another

You can use conditional forwarders in your DNS servers.

http://msmvps.com/blogs/ad/archive/2008/09/05/how-to-configure-conditional-forwarders-in-windows-server-2008.aspx

http://www.windowsnetworking.com/articles_tutorials/DNS_Conditional_Forwarding_in_Windows_Server_2003.html

what happens if you ping full hsot name?

ping hostname.domain.com

?

probably your domains have no information in DNS suffix order. Create a GPO in each domain and define FQDN list for those domains.

In the first add

domain1.com (its domain)
domain2.com (remote domain)

in the second domain add

domain2.com (its domain)
domain1.com (remote domain)

Regards,
Krzysztof

I have entred the DNS entry in Forwarders , AD server is able to resolve to one another  But the Domain members are not able to resolve it

iSiek, is correct. After reading your question agian it sounds like you are having problems with shortname resolution. Adding a domain suffix to your computers will fix this and using a GPO is the easiest way..

Isiek they are not able to resolve using FQDN also

If they are not able to resolve FQDN then the conditional forwarders should have fixed that. Are you running 2003 or 2008 for your DNS servers? If 2003 you will need to add them on each server unless you add them to the application partition.
Is there a firewall between the servers?

Check Ken's suggestion and additionally type in command-line

nslookup hostnameDomainA.fqdn
nslookup hostnameDomainB.fqdn

and check if DNS server resolved those names.

Krzysztof

On both  server DNS Stub zone was created for DNS resolution .