Right now there is only one brand of polyisoprene condoms available - SKYN condoms from Lifestyles. They are slightly more expensive than natural latex condoms, but much cheaper than polyurethane condoms, which are the other alternative for people with latex allergies.
Ease of Acquisition:
The SKYN polyisoprene condom is available at many drugstores and also online.
Use During Vaginal Intercourse:
Polyisoprene condoms were FDA approved for the prevention of pregnancy and sexually transmitted diseases in 2008. As such, they are suitable for use during vaginal intercourse.
Use During Oral Sex:
Polyisoprene condoms are fine for use during oral sex.
Use During Anal Sex:
Polyisoprene condoms can be used anywhere latex condoms can, including for anal sex. Just don't forget the lube.
In November 2008, the FDA approved the first polyisoprene condom for prevention of pregnancy and sexually transmitted diseases. The SKYN condom, made from polyisoprene, has been making a lot of waves in the short time it has been on the market. It is much stretchier, and more form fitting, than the other alternative for people with a latex allergy, polyurethane condoms, and it is also significantly cheaper. In addition, the sensation of using these condoms is different enough that some people prefer them to natural latex condoms even if they don't have latex allergies. The main downside is that these polyisoprene condoms are slightly thicker than polyurethane condoms, but for many individuals the benefits will be a worthy trade-off.
Please note: Polyisoprene is, chemically, the same type of rubber as latex, however synthetic polyisoprene condoms should not contain the natural proteins that are the source of most people's latex allergies.