winbuckshot,
Some new terms we will have to get used to and they (as Microsoft tends to with its naming) will likely cause confusion:
Windows Live Mail .... the new version of Hotmail. As David says, this will be web based reading of mail and will not be scanned by the avast mail scanner.
Windows Live Desktop ... the new version of Outlook Express. This will be a desktop mail client just as OE is and, although I have not tested it yet, it says it will include POP3 accounts as well as access to Hotmail. The access to Hotmail is interesting since it may mean free client access to Hotmail for all again ... we will have to wait and see the details.
As for Webmail to POP3 converters - some names for you to look up:
YPops (free) - allows you to receive and send mail from a free Yahoo account.
MrPostman (free) - allows you to receive mail from free Yahoo, Hotmail, GMail** and a range of other Webmail services. Provides very limited sending on Hotmail.
FreePops (free) - allows you to receive mail from free Yahoo, Hotmail, GMail and a large range of other Webmail services. Strictly read only - sending is expected to be via SMTP server provided by your ISP.
HotPop (shareware Boolean Dream product) - Allows you to receive/send email from/to WebDav enabled Hotmail accounts. WebDav means either you pay for your Hotmail account or you have been granted continued free access on some very old free Hotmail accounts.
For Thunderbird client users there is a set of Webmail extensions that allow you to receive/send from/to free Hotmail, Yahoo, Gmail, Lycos, AOL mail and others.
Use of any of these products means that the mail can be scanned by avast. The only extra issue in avast is that since the POP3 transfer of mail from the program to your client occurs inside your system it is not scanned by avast by default. To ensure this mail is scanned in the Internet Mail provider:
Customize > Redirect tab > Uncheck the 'Ignore local communications' box.
**GMail - provides secure POP3/SMTP access which cannot be scanned by avast unless a third party program, STunnel, is used to manage the secure session. Gmail reports that attachments are scanned within GMail, but it does not say that the message body is scanned. The above services access GMail via the web interface and convert the mail to POP3 - so avast can scan the whole message.
A final word of warning.
Almost all of these programs (except HotPop and the support for WebDav Hotmail accounts in the Thunderbird extensions) work by what is called "screen-scraping". Behind the scenes they have to perform the web transactions in a similar way to what you would do to access your mail via the web. The program then interprets the responses converts them to a POP3 stream suitable to be read by your mail client. This oversimplifies a bit - but is essentially correct.
The downside of this is that every so often a Webmail service will change the way its Web transactions look/work. Then the webmail converter fails to see what it looking for and it is out of action until the developer investigates what has changed and modifies the product to interpret the Webmail results again. So if Hotmail makes a change (as it doing with Hotmail Live at the moment) all of the products break for Hotmail at the same time. Fortunately there seems to be some friendly rivalry out there about getting things working quickly again.
Hope this helps.