We have a troubble's with hotmail, but we solved adding SPF in DNS 
Record (TXT Record) descending the number of containers to 20 (greater 
to 20 it rejects you)

this link can help you to create your spf

http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/default.aspx

I hope serves to you as aid


John Lyon wrote:
>>   Hi all,
>>
>>    Some of my subscribers using hotmail & MSN are
>>  having trouble getting their mail from the group.
>>  Even though the list is on their *safe list*, the
>>  email doesn't get through to them anyway. 
>>
>>   Does anyone else have this experience with this,
>>  and are there things we as list owners to do to
>>  advise and help them?
>>     
>
> I would have to say everyone has experienced this. The causes are 
> many whether it's hotmail & MSN or anyone else. On your end make sure 
> their subscription options are in order. Then check your mailer's 
> queue to make sure the mail isn't backing up. Then check the mailer 
> logs for the connection with hotmail & MSN. There you will find proof 
> they are either accepting the mail or rejecting it.
>
> If all is well on your end, all you can do is advise them you have 
> proof that their mail is being delivered. They will then have to 
> complain to hotmail & MSN.
>
>
>